Image Resizer

Every Platform Has a Different Opinion About Image Size

Instagram crops a square post at 1080×1080px but displays it at 293px in grid view. LinkedIn shows banner images at 1584×396 but renders them at different sizes on mobile vs desktop. YouTube thumbnails must be 1280×720 to display without letterboxing in search results. Facebook Open Graph images look fine at 1200×630 but get aggressively re-cropped at other sizes. Getting these dimensions right is not pedantic — it is the difference between a crisp, full-frame image and one that arrives cropped at someone's forehead or stretched to fill an unexpected aspect ratio. The ToollyX Image Resizer includes ten pre-built presets covering the most common platform requirements, plus pixel and percentage modes for any custom dimension.

Pixels Mode vs Percentage Mode — Which to Use When

By Pixels is for when you have a specific target dimension — a platform requirement, a design spec, a CMS that expects 800×600, or a print size at a known DPI. Lock Ratio calculates the missing dimension automatically based on the original aspect ratio, preventing distortion. Unlocking ratio lets you set both dimensions independently, which is correct for platform presets that require a specific aspect ratio regardless of the source image's proportions. By Percentage is for proportional scaling when you want to reduce all images in a batch by the same factor — 50% halves both dimensions (and reduces file area by 75%), 200% doubles them. This is useful for creating @2x retina versions from standard assets, or reducing a batch of camera photos to a consistent output size relative to their original dimensions rather than a fixed pixel target.

The Social Media Presets in Detail

Each preset sets both dimensions and switches to pixel mode automatically. HD 1080p (1920×1080) — standard widescreen for presentation slides, desktop wallpapers and YouTube channel art backgrounds. Instagram Post (1080×1080) — square format for feed posts. Instagram also accepts 4:5 vertical (1080×1350) and 1.91:1 landscape (1080×566) for feed, but 1:1 is the safest universal option. Instagram Story (1080×1920) — full-frame 9:16 vertical. Facebook Cover (851×315) — desktop cover photo size; mobile crops the top and bottom, so keep key content in the centre 640×315 area. Twitter Header (1500×500) — displays cropped to roughly 1500×500 on desktop and 600×200 on mobile. YouTube Thumbnail (1280×720) — 16:9 at 72 DPI minimum; YouTube recommends keeping file size under 2 MB. LinkedIn Banner (1584×396) — profile background banner. OG Image (1200×630) — Open Graph image for link previews on Facebook, Twitter, Slack, iMessage and most messaging apps.

Lock Ratio and Distortion Prevention

Resizing with Lock Ratio off and both dimensions set manually will stretch or squash the image if the target aspect ratio differs from the source. This is sometimes intentional — fitting an image into a fixed container at a platform- specified ratio — but usually creates an uncanny, distorted result for photographic content. Lock Ratio prevents this by recalculating the height whenever the width changes (and vice versa), using the original aspect ratio as the constraint. When a preset is applied, Lock Ratio is automatically disabled because platform dimensions represent a hard target, not a proportional scale. For images that need both cropping to a specific ratio and resizing to specific dimensions, the correct workflow is: crop to the target ratio first using the Image Cropper, then resize to the exact pixel target here.

Output Quality and Format for Resized Images

Resizing upward — increasing dimensions beyond the source image's original size — never adds detail. The browser interpolates new pixels from existing ones, which softens the image. If you are creating a 1920px wide hero from a 600px source, the result will look blurry regardless of quality setting. Always start from the largest available source file. Resizing downward, by contrast, produces sharp results because multiple source pixels are averaged into each output pixel. For web output, WebP at quality 82–85% gives the best combination of sharpness and file size after downscaling. For print output, PNG at full quality or JPG at 90%+ preserves all the detail the resized dimensions can contain. After resizing, run large files through the Image Compressor to reduce file size before deploying to a website or sending as an attachment.

Batch Resizing — Preparing a Full Image Set at Once

Drop multiple images simultaneously and the resizer applies the same settings to all of them in parallel. This is practical for preparing an entire product image library for an eCommerce site, converting a set of raw exports to thumbnail size for a blog index, or generating all social media versions of a promotional image in one session. Each output file keeps its original filename with the new dimensions appended — photo-1920x1080.jpg — so you can identify files by size in a download folder without opening them. If you need all downloaded files in a specific format regardless of their original format, set the Output Format selector to JPG, PNG or WebP before generating.

✓Verified by ToollyX Team · Last updated June 2026