You upload a wide, sharp image to SharePoint. It looks fine on your laptop, blurry on a larger screen and badly cropped on a phone.
The usual reaction is to search for “the SharePoint banner size”. That search goes wrong because SharePoint has several different things that people call a banner or header.
There is no single universal size.
The correct preparation depends on whether you are editing:
- the site header at the top of every page
- the page title area, now presented as the first Banner web part in the page editor
- an Image or Hero web part in a full-width page section
- an ordinary image inside a one-, two- or three-column section
This guide separates those surfaces, gives Microsoft's documented dimensions and explains why responsive cropping matters more than a mythical 72 DPI setting.
The size table
| SharePoint surface | Microsoft's current guidance | What to do |
|---|---|---|
| Extended site-header background | 2560 × 164 px; JPEG or PNG | Use a very wide, shallow image. Keep the subject near the focal point and avoid baked-in text. |
| Full-width page column | Source image at least 1920 px wide | Let SharePoint set the responsive height. Use the aspect ratio required by the web part. |
| Page title/Banner area | Landscape, preferably 16:9 or wider; set a focal point | Start with a good landscape source, then test the crop in the page, thumbnail, search and mobile views. |
| Hero – Tiles | Web part about 8:3; images within it crop around 4:3 | Place the subject safely inside the frame and set the focal point. |
| Hero – Layers | Each layer about 8:3; images within layers near 16:9 | Use landscape images with space around the subject. |
| Hero – mobile | Carousel presentation at 16:9 | Test on a narrow viewport; desktop composition will not survive unchanged. |
| One-column image | At least 1204 px wide | 1204 × 677 for 16:9; 1204 × 903 for 4:3. |
| Two-column image | At least 586 px wide per column | 586 × 330 for 16:9; 586 × 439 for 4:3. |
| Three-column image | At least 380 px wide per column | 380 × 214 for 16:9; 380 × 285 for 4:3. |
| Standard site logo | 192 × 64 px | PNG or JPEG; SVG is available with documented site-type restrictions. |
| Site-logo thumbnail | 64 × 64 px | Make this a simple square mark that remains recognisable when small. |
| Extended-header site logo | 300 × 64 px | Use a transparent asset where the design needs it. |
Those figures come from Microsoft's current image sizing and scaling guidance. They are source and layout guidance—not a promise that every pixel remains visible on every screen.
First identify which “header” you are editing
1. The site header
The site header contains the site logo, site title and navigation and appears across the site.
Open Settings > Change the look > Header. In Microsoft's current header settings, the Extended layout can have a background image. That is the surface for the official 2560 × 164 px recommendation.
This is a very shallow ratio. A normal 16:9 photograph will lose most of its top and bottom if you try to force it into the space.
Prepare the composition for the strip:
- keep the meaningful subject near the centre or chosen focal point
- leave calm space around it for responsive crop changes
- do not put a sentence, date or phone number inside the image
- check that the site title and navigation remain readable over the overlay
Microsoft lets editors adjust the image, overlay, opacity and focal point. Use those controls before changing the source file again.
2. The page title or Banner web part
This is the large area at the top of one SharePoint page or news post. Microsoft's page editor now refers to the first area as the Banner web part; older documentation and many users still call it the title area.
Microsoft recommends a landscape image at 16:9 or wider and tells editors to set a focal point. The same image may also feed the page thumbnail shown in search, News and Highlighted content, so the crop is not limited to the page you are editing.
Use Edit > select the Banner web part > Change image, then choose Set focal point. Put the focal point on the person, object or detail that must survive cropping.
Do not use a page-title image as a poster. Keep the title as native SharePoint text so that it remains readable, accessible and responsive.
3. A full-width Image or Hero web part
A full-width column is a page section, not the site header. Modern communication-site pages support this layout; Microsoft's developer guidance confirms that the full-width column is an additional communication-site layout.
Microsoft's image-sizing page recommends a source at least 1920 px wide for a full-width column. SharePoint displays it across the available screen width and calculates the height responsively.
The web part still controls the crop:
- An Image web part expands to the section width and can be cropped to an aspect ratio.
- A Hero web part has its own Tiles, Layers and Carousel rules.
- A custom SharePoint Framework web part must explicitly support the full-width column; a generic web part cannot be forced into it with a magic image size.
If the Full-width section option is missing on a team site, that is a page-layout boundary—not an image error.
Why 3840 × 900 PNG at 72 DPI is not the answer
The old version of this article presented that combination as a universal fix. Microsoft does not.
DPI does not control browser sharpness
DPI is print metadata. On a SharePoint page, the important measurements are the image's pixel dimensions, the size at which the browser displays it and the way SharePoint crops or serves a rendition.
Changing a file from 300 DPI to 72 DPI without changing its pixel dimensions does not create new detail or fix the composition.
Bigger is not automatically better
An oversized source can slow the page and still look wrong after SharePoint crops it. Microsoft's modern image-optimisation guidance says Page Diagnostics flags pages containing an image over 300 KB and recommends optimising images before upload.
The same guidance explains that SharePoint serves image renditions based on the browser window and client display. Very large images may be reduced, which can produce unexpected rendering.
There is a wrinkle worth knowing: Microsoft's image-sizing page also says page-title images look best when they are at least 1 MB. That conflicts with the separate performance guidance that flags images over 300 KB.
Do not turn either file-weight number into a blind rule. Use sufficient pixel dimensions and the correct ratio, compress sensibly, then inspect the visual result and Page Diagnostics on the actual page.
PNG is not always better than JPEG
Choose the format for the artwork:
- JPEG is normally efficient for photographs and soft gradients.
- PNG suits flat graphics, transparency and sharp interface-style artwork, but photographic PNGs can become unnecessarily large.
- SVG can be appropriate for supported logo surfaces, but Microsoft documents restrictions for SVG site logos on group-connected sites.
For the extended site-header background, Microsoft explicitly lists JPEG and PNG. It does not say every banner must be PNG.
How SharePoint responsive cropping works
Modern SharePoint pages reflow as the viewport changes. A full-width image can span 1920 pixels or more on a desktop and then appear inside a narrow mobile composition.
SharePoint cannot keep the same wide rectangle and make every part readable without either:
- shrinking it until it becomes tiny
- adding empty bands
- or cropping it
The page and web parts choose cropping. The focal point tells SharePoint which part deserves protection as the frame changes.
This is why text inside the image is fragile. A headline positioned at the left edge may work on a desktop and disappear on mobile. Native page text can reflow; pixels baked into a picture cannot.
A practical safe-area method
When preparing a wide image:
- Place the main subject near the centre third of the image.
- Leave expendable background on both sides.
- Avoid important detail at the extreme top and bottom.
- Keep all headings, dates and calls to action as SharePoint text.
- Set the focal point in SharePoint after upload.
- Preview the page at desktop, tablet-like and narrow phone widths.
- Check any search, News or Highlighted content thumbnail that uses the image.
This does more for a stable result than doubling the source width.
Prepare an extended site-header background
Use this route only when you mean the site-wide Extended header.
- Create a 2560 × 164 px canvas.
- Use JPEG for a photograph or PNG for flat/transparency-based artwork.
- Keep the subject and any brand shape away from the extreme edges.
- Export an optimised web file. Do not include essential wording in the image.
- In SharePoint, open Settings > Change the look > Header.
- Select Extended layout.
- On the Design tab, upload the background image.
- Adjust the overlay, opacity and focal point.
- Confirm that the site logo, title and navigation remain readable.
- Save, then test the home page and at least one interior page at several widths.
Microsoft notes that Minimal and Extended header layouts can be temporarily unavailable in GCC, GCC High, DoD, Gallatin and Sovereign clouds. If the option is absent in one of those environments, check the current Microsoft support note before trying to recreate it with CSS.
Prepare a full-width page image
- Confirm that you are editing a modern communication-site page.
- Choose a source at least 1920 px wide.
- Pick a 16:9 or 4:3 composition where the chosen web part supports it.
- In the page editor, add a Full-width section.
- Add a supported Image or Hero web part.
- Upload or select the image.
- Crop using the web-part controls and set a focal point where available.
- Publish only after checking desktop and mobile crop behaviour.
If you use an Image web part, Microsoft's Image web part guide supports 16:9, 3:2, 4:3, 1:1 and free-ratio crops. It also lets you add or correct alternative text.
Prepare Hero images without losing the subject
The Hero web part is deliberately dynamic. One source image is not displayed as one fixed rectangle in every layout.
Microsoft's documented ratios are:
- Tiles: the web part follows roughly 8:3; images inside it crop around 4:3
- Layers: each layer follows roughly 8:3; its image crops near 16:9
- Mobile: Hero uses a 16:9 carousel presentation
Choose images with room around the subject and set the focal point for each tile, layer or slide. Microsoft's Hero web part guide shows the current control.
If your artwork includes a call to action, use the Hero web part's own header and call-to-action fields. Do not flatten the words into the photograph.
Fix a blurry or badly cropped image
1. Confirm the surface
Is it an Extended site header, page Banner, Hero, Image web part or page thumbnail? Use the matching guidance from the table. Resizing for the wrong surface creates another wrong crop.
2. Inspect the original pixels
A 900-pixel-wide source cannot fill a 1920-pixel-wide column sharply. Replace it with a larger original instead of repeatedly re-exporting the small file.
3. Match the aspect ratio
If the source is tall but the destination is shallow, SharePoint must crop heavily. Recompose the image for the destination ratio.
4. Reset the crop and focal point
Open the web-part controls, reset earlier crops and set the focal point on the meaningful subject. A technically large image can still look broken when the crop protects an empty corner.
5. Remove baked-in text
Recreate headings and calls to action with SharePoint fields or a Text web part. This improves mobile behaviour, searchability and accessibility.
6. Optimise file weight
Export the smallest file that remains visually acceptable. For page images, run the Page Diagnostics for SharePoint tool and inspect the Large images result.
7. Check permissions and source location
An image selected from a restricted library can be visible to the page author but not to every page reader. The Image web part may prompt authors to copy a source into Site Assets so that page viewers can load it.
Accessibility and brand checks
Use real text
Do not place instructions, event details or section headings only inside the picture. Real page text can resize, reflow, translate and be read by assistive technology.
Review alternative text
The Image web part can generate automatic alternative text, but Microsoft tells authors to review it. Replace vague or inaccurate text with a short description of the information the image conveys.
For a purely decorative background that adds no information, do not invent a verbose description. Keep the meaningful page title and navigation available as native text.
Check contrast after the overlay
The desktop image is not the only variable. The theme, overlay, opacity and mobile crop all affect the contrast behind navigation or title text. Test the published combination, not the image file by itself.
Confirm image rights
Microsoft's Image and Hero pickers can surface stock images and Bing results, but the editor remains responsible for checking the licence. An image appearing in a picker is not blanket permission for every commercial use.
Avoid custom CSS for a normal banner problem
Do not inject CSS to target SharePoint's generated class names just to hold one crop in place. Microsoft can change internal markup and class names, and a fixed desktop height often makes mobile behaviour worse.
Use the supported site-header, section, Image and Hero controls first.
If you are building a genuine custom SharePoint Framework web part, full-width support is an explicit component decision. Microsoft requires the web-part manifest to declare supportsFullBleed: true. That is a development route with its own responsive and accessibility testing—not a quick patch for an ordinary editor.
Frequently asked questions
What is the correct size for a SharePoint Extended header background?
Microsoft recommends 2560 × 164 pixels in JPEG or PNG format for the Extended site-header background.
What size should a full-width SharePoint page image be?
Microsoft recommends an image at least 1920 pixels wide for a full-width column. The height is responsive and the Image or Hero web part controls the aspect ratio and crop.
Should every SharePoint banner be 3840 × 900 PNG at 72 DPI?
No. Microsoft does not publish that as a universal standard. Browser sharpness depends on pixel dimensions and displayed size, while the required ratio varies by site header, page Banner, Image web part and Hero layout.
Why does SharePoint crop a 16:9 image?
The destination frame changes with the web part, layout and screen width. Set a focal point and leave space around the subject so the responsive crop can change safely.
Is PNG always the best format for a SharePoint banner?
No. JPEG is usually more efficient for photographs; PNG suits flat artwork and transparency. Microsoft supports both for the Extended header background. Choose by image type and measured file weight.
The rule worth remembering
Do not ask for “the SharePoint banner size” until you know which SharePoint surface you mean.
For an Extended site header, start at 2560 × 164. For a full-width page column, start at least 1920 pixels wide. For a page Banner or Hero, design around the documented aspect ratio, then set the focal point and test the crop.
That is less exciting than a magic 4K export setting. It is also how SharePoint actually works.
For practical SharePoint design, permissions and governance fixes that have been checked against current Microsoft documentation, join the SharePoint & Teams Admins Space.
How this article was checked
This rewrite was fact-checked on 13 August 2026 using Microsoft Learn MCP search and full-page retrieval. The primary references were Microsoft's image sizing and scaling guide, site-header settings, Image web part, Hero web part, full-width column boundary and modern image optimisation.