How do I resize an image to 851x315?

Upload your image — the resizer is pre-set to 851×315px. Turn off "maintain aspect ratio" for an exact 851x315 canvas, or keep it on with the blurred-background fill, then download.

What is 851x315 used for?

851×315 is commonly used for Facebook cover photos.

Will resizing to 851x315 stretch my photo?

Only if you turn off the aspect-ratio lock without the fill option. With the blurred-background fill, your subject stays undistorted inside the 851x315 frame.

Is the 851x315 resizer free?

Yes — resize and download without creating an account. Images are auto-deleted after processing.

Processed output — A photo and its 851×315 version, resized without stretching, with both pixel sizes shown.

Source — A photo and its 851×315 version, resized without stretching, with both pixel sizes shown.

Image Optimization

Resize Image to 851×315 px

Resize to 851 × 315

Dimensions loaded automatically

Resize any image to exactly 851×315 pixels online — ideal for Facebook cover photos. Upload a JPG, PNG or WebP and the tool is pre-set to 851×315; keep the aspect ratio or fill the frame with a blurred background. Free, fast and processed securely.

Exact 851 × 315 px upload requirements
Social, listing, thumbnail, or presentation canvases
Consistent image dimensions without silent stretching

Resize to 851 × 315

Dimensions loaded automatically

Drop an image — set exact dimensions and download the resized file

Upload an image

Drop a file here, or click to browse

Supported formats include JPG, PNG, GIF, WebP, SVG, HEIC, AVIF, TIFF, RAW, PSD. Maximum file size: 20 MB.

Sizing a Facebook Page cover photo at 851 × 315

851 × 315 comes from Facebook's help center, which says a Page cover photo loads fastest as an sRGB JPG file that is 851 pixels wide, 315 pixels tall and less than 100 kilobytes. The same page sets a minimum of 400 pixels wide and 150 pixels tall.

The shape is very wide, about 2.7:1, so most photos need a decision. Facebook displays the cover with different proportions on computers and on phones, and on mobile the profile picture overlaps the cover by about 40 pixels, so keep faces, logos and text in the middle band. With the aspect lock on, an ordinary photo becomes a narrow strip with fill at the sides; for an edge-to-edge cover, crop a wide band from the photo first. Extend background with AI does not support this shape.

This page saves a JPG, the format the help center mentions. To meet its size suggestion, compress the cover under 100 KB after resizing and check that small text still reads. For profile pictures, posts and a larger cover preset, see the Facebook resizer.

Before you upload the cover

Keep text and faces in the central band
Allow for the profile picture overlapping part of the cover on mobile
Preview the cover on both a computer and a phone

Image OptimizationPreset loaded automatically

Set up for Resize Image to 851×315 px

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Prepared settings

Starting point: One source image at its original dimensions; Upload a JPG, PNG, or WebP; the exact output canvas is already entered.
Prepared target: 851 × 315 px; Width and height are prefilled from this page, so neither number needs to be entered manually.
Composition: Aspect lock and background fill remain adjustable; Keep proportions, crop, or add a fill treatment instead of silently stretching the subject.
Review rule: Verify a 851 × 315 px download; Inspect framing and edge treatment in the preview before using the image on its destination.

Best-fit uses

Exact 851 × 315 px upload requirements
Social, listing, thumbnail, or presentation canvases
Consistent image dimensions without silent stretching

Frequently asked questions

How do I resize an image to 851x315?: Upload your image — the resizer is pre-set to 851×315px. Turn off "maintain aspect ratio" for an exact 851x315 canvas, or keep it on with the blurred-background fill, then download.
What is 851x315 used for?: 851×315 is commonly used for Facebook cover photos.
Will resizing to 851x315 stretch my photo?: Only if you turn off the aspect-ratio lock without the fill option. With the blurred-background fill, your subject stays undistorted inside the 851x315 frame.
Is the 851x315 resizer free?: Yes — resize and download without creating an account. Images are auto-deleted after processing.

What you can do with Image Resizer

Review the main capabilities before you begin.

Resize images to an exact width and height
Scale photos up or down by percentage
Fit ready-made social media dimensions
Create passport and ID photo sizes
Keep the aspect ratio while resizing
Add a solid or blurred background to fill space
Bulk-resize many images into one ZIP

Use this tool

Settings reference

Available controls for Image Resizer.

Mode

Single image / BatchPresets: Switches between resizing one photo and resizing many at once — Batch applies the same size and output settings to every image and downloads the results together as a ZIP.Options: Single imageBatch

Size

Width (px)Number inputRange: 1–8192px: Sets the exact output width in pixels, up to 8192; with the aspect-ratio lock on, the height updates automatically to match.
Height (px)Number inputRange: 1–8192px: Sets the exact output height in pixels, up to 8192; with the aspect-ratio lock on, the width updates automatically to match.
Maintain aspect ratioOn / Off: Keeps width and height in proportion so the photo is not stretched — edit one dimension and the other adjusts to preserve the original shape. On by default.
Resize by PercentagePresets: Scales the image relative to its own size — pick a percentage instead of calculating exact pixels; in Batch mode each image is scaled from its own dimensions.Options: 25%Half (50%)75%Original (100%)2x (200%) Enlarge
Social Media SizesPresets: One-click presets that fill in the exact pixel dimensions for Facebook, Instagram, Twitter and YouTube profile pictures, posts, stories and covers.Options: Facebook ProfileFacebook ImageFacebook CoverFacebook Event ImageFacebook Group PhotoInstagram PostInstagram StoryTwitter PostTwitter ProfileTwitter Header CoverYouTube ProfileYouTube Cover
Passport SizesPresets: Starting presets for common passport and ID photo dimensions. Use one only when it matches the receiving authority's current size and delivery instructions.Options: 2.5cm x 3.5cm3.5cm x 3.5cm3.5cm x 4.5cm

Background

Add Background ColorOn / Off: Pads empty space with a solid color when the target size does not match the photo's proportions, instead of stretching or cropping; it becomes selectable once Use Blur Background is switched off, since only one fill can be active.
Background colorColor picker: Picks the fill color for the padded area — use the color picker, type a hex code, or tap a quick swatch (blue, white, black, light gray). Shown when Add Background Color is on.
Use Blur BackgroundOn / Off: Fills empty space with a softly blurred, zoomed copy of the photo itself so mismatched aspect ratios look natural; on by default, it always keeps the photo's proportions and locks out the solid color fill while active.
Blur IntensitySliderRange: 5–50 · Default: 20: Controls how soft the blurred background fill looks, from 5 (light) to 50 (heavy); higher values make the padding more abstract so the subject stands out. Shown when blur background is on.

Output

QualitySliderRange: 10–100% · Default: 92%: Sets compression for the resized output — higher keeps more detail with a larger file, lower gives smaller files for faster uploads and sharing.
Output FormatDropdown: Chooses the file type of the resized image independently of the source format — JPEG for small photos, PNG for graphics, WebP for modern web use, or GIF.Options: JPEGPNGWebPGIF

AI extension

Extend background with AIOne-click: Continue the scene into the selected size with AI while keeping the prepared source photo. Uses your AI allowance with free downloads up to 800px on the longest side. Premium or credits unlock full resolution. Supported ratios require maintaining aspect ratio. In Batch, every queued image is extended and delivered at the size and format you chose.

Open this tool

Resize to a popular size

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How Image Resizer helps you get it done

Real problems it solves every day — for businesses, creators, and everyday tasks. Find the use case that fits you and start.

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Official Documents

Common ID-Photo Size Starting Points

Use the 2.5x3.5cm, 3.5x3.5cm or 3.5x4.5cm presets when they match a requested image size. This general resizer does not check identity-photo rules; verify dimensions, editing and delivery with the receiving organization.

Productivity

Batch-Resize an Entire Shoot for Delivery

Switch to Batch mode and apply a single percentage or pixel target across dozens of photos at once, then hand a client a ready-to-use ZIP instead of resizing each image by hand.

For E-commerce

Square Thumbnails Without Cropping the Subject

Turn on Add Background Color or Use Blur Background so a photo with the 'wrong' aspect ratio still fills a square product-grid or app-icon slot without chopping off part of the subject.

Web & SEO

Shrink Page Weight by Converting Format on the Fly

Combine the Output Format switch (to WebP) with the Quality slider while resizing so the same step that fits your layout also cuts file size for faster Core Web Vitals scores.

Social Media

One-Click Sizing for Every Social Platform

Pick a built-in Facebook, Instagram, Twitter or YouTube preset (profile, cover, post or story) to get the exact pixel dimensions each platform recommends in a single click, instead of looking up and typing each network's spec by hand.

Try Image Resizer now — it's free