# FileBelow > A free, browser-based tool that makes an image meet a stated requirement — > a maximum file size, exact pixel dimensions, an aspect ratio, or a file > format — at the highest quality that requirement allows. All processing runs > on the user's own device; images are never uploaded. This file is a supplementary orientation document for automated readers. It is not a standard, it confers no ranking or citation advantage, and no search or AI system is obliged to read it. It exists because a short, accurate, plain description of a site is cheap to provide and occasionally useful. The authoritative source for anything below is the linked page. ## What FileBelow does FileBelow takes the requirement as its input rather than offering a quality slider to guess with. You state the limit; it works backwards to the best image that meets it. Its distinguishing technique is a two-axis search. File size is governed by two things — how many pixels an image has, and how hard the encoder compresses each one. Most tools vary only the second, which at tight budgets produces visible blocking and smeared detail. FileBelow encodes candidates across several resolutions and quality settings, scores each against the original using a structural similarity measure, and returns the highest-scoring one that fits. Measured on a 4032×3024 photograph, against a quality-only search at the same target: +1.6 SSIM at 500 KB, +5.9 at 200 KB, +8.9 at 100 KB. Below roughly 50 KB a quality-only search at full resolution cannot reach the target at all. ## Facts - **Cost:** free. No account, no sign-up, no upload quota, no watermark, no paid tier. - **Privacy:** images are processed in the browser. The site is static and has no server that could receive an image. Verifiable in a browser network panel. - **Input formats:** JPG/JPEG, PNG, WebP, HEIC/HEIF, AVIF, BMP, still GIF. - **Output formats:** JPG/JPEG, PNG, WebP, and PDF from the image-to-PDF tool. - **AVIF:** read but not written. Browsers can decode AVIF and cannot reliably encode it, and all processing here happens on the visitor device, so offering AVIF output would work on some machines and fail on others. - **Animated images:** rejected explicitly rather than silently flattened to a still. - **Metadata:** EXIF, including GPS location, is removed as a result of re-encoding. - **Rotation:** EXIF orientation is baked into the pixels, so output is upright in software that ignores metadata. - **Units:** 1 KB is treated as 1,000 bytes and 1 MB as 1,000,000 bytes — the smaller of the two common readings, so a file satisfies either. - **Browsers:** works in Chrome, Firefox, Safari and Edge, on desktop and mobile. Where the browser lacks OffscreenCanvas, processing runs on the main thread instead. ## Tools Fourteen tools, one engine. All of them run in the browser. - [All tools](https://filebelow.com/tools) - [Image compressor](https://filebelow.com/tools/image-compressor): compress to a maximum file size. - [Image resizer](https://filebelow.com/tools/image-resizer): resize to exact pixel dimensions. - [Image converter](https://filebelow.com/tools/image-converter): convert between JPG, PNG and WebP; read HEIC, AVIF and BMP. - [Image cropper](https://filebelow.com/tools/image-cropper): crop to a ratio or freely. - [Requirement checker](https://filebelow.com/tools/image-requirement-checker): check an image against a named platform and report every rule that fails. - [Rotate an image](https://filebelow.com/tools/rotate-image): quarter turns and mirroring, applied to the pixels. - [Add a border](https://filebelow.com/tools/add-border-to-image): padding, or reaching a shape without cropping. - [Add a watermark](https://filebelow.com/tools/image-watermark): text or a logo image, positioned or tiled. - [Images to PDF](https://filebelow.com/tools/image-to-pdf): up to 30 images into one document, written in the browser. - [Merge images](https://filebelow.com/tools/merge-images): join images side by side, stacked or in a grid without stretching them. - [Remove metadata](https://filebelow.com/tools/remove-exif-data): show what EXIF, GPS and other blocks a file carries, then remove them. - [Change DPI](https://filebelow.com/tools/change-image-dpi): write a print resolution, and report the pixel count a print size actually needs. - [Aspect ratio calculator](https://filebelow.com/tools/aspect-ratio-calculator): solve for width or height at a fixed ratio. Needs no file. - [Best image format](https://filebelow.com/tools/best-image-format): encode a file as JPEG, WebP and PNG and report the measured sizes. ## Compress to a specific size - [100 KB](https://filebelow.com/compress-image-to/100kb) - [500 KB](https://filebelow.com/compress-image-to/500kb) - [1 MB](https://filebelow.com/compress-image-to/1mb) - [2 MB](https://filebelow.com/compress-image-to/2mb) - [All size targets](https://filebelow.com/tools/image-compressor) ## Convert between formats - [HEIC to JPG](https://filebelow.com/convert/heic-to-jpg) - [PNG to JPG](https://filebelow.com/convert/png-to-jpg) - [PNG to WebP](https://filebelow.com/convert/png-to-webp) - [JPG to WebP](https://filebelow.com/convert/jpg-to-webp) - [HEIC to PNG](https://filebelow.com/convert/heic-to-png) - [WebP to JPG](https://filebelow.com/convert/webp-to-jpg) - [WebP to PNG](https://filebelow.com/convert/webp-to-png) - [JPG to PNG](https://filebelow.com/convert/jpg-to-png) - [AVIF to JPG](https://filebelow.com/convert/avif-to-jpg) - [JPG to PDF](https://filebelow.com/convert/jpg-to-pdf) - [PNG to PDF](https://filebelow.com/convert/png-to-pdf) ## Resize to specific dimensions - [1080 x 1080](https://filebelow.com/resize-image-to/1080x1080) - [1920 x 1080](https://filebelow.com/resize-image-to/1920x1080) - [1280 x 720](https://filebelow.com/resize-image-to/1280x720) - [1200 x 630](https://filebelow.com/resize-image-to/1200x630) - [1080 x 1350](https://filebelow.com/resize-image-to/1080x1350) - [1080 x 1920](https://filebelow.com/resize-image-to/1080x1920) ## Platform image requirements A directory of image specifications for named destinations. Every entry was read off the platform's own published documentation; each page displays the source link and the date it was checked. Where a platform documents dimensions but not a byte ceiling, the ceiling is left blank rather than estimated. Destinations that could not be sourced to an official page are absent by choice, not by oversight. - [All destinations](https://filebelow.com/image-size) - [Changelog of specification changes](https://filebelow.com/changelog) - [The whole database as JSON](https://filebelow.com/image-size/specs.json): every record with its source URL and verification date. Free to use, served with permissive CORS headers. The dates are the guarantee: a record is accurate as of lastVerified and not afterwards. ## Explanations - [How to get an image under a size limit](https://filebelow.com/learn/under-a-size-limit) - [Why websites reject your images](https://filebelow.com/learn/why-websites-reject-images) - [HEIC explained](https://filebelow.com/learn/heic-explained) - [JPEG vs PNG vs WebP](https://filebelow.com/learn/jpeg-png-webp) - [What happens to quality when you compress](https://filebelow.com/learn/what-happens-when-you-compress) - [What image dimensions actually mean](https://filebelow.com/learn/image-dimensions) - [Why your phone photo is 8 MB](https://filebelow.com/learn/why-your-phone-photo-is-8mb) - [How to fix a sideways photo](https://filebelow.com/learn/fix-a-sideways-photo) - [Photos and signatures for an application form](https://filebelow.com/learn/image-for-job-application) - [When a scanned document is too large](https://filebelow.com/learn/scanned-document-too-large) - [DPI, PPI and resolution explained](https://filebelow.com/learn/image-dpi-explained) - [Aspect ratio explained](https://filebelow.com/learn/aspect-ratio-explained) - [Crop, or add borders?](https://filebelow.com/learn/crop-or-add-borders) - [What EXIF data is](https://filebelow.com/learn/what-is-exif-data) - [Does a watermark protect your photos?](https://filebelow.com/learn/watermarking-photos) - [All explanations](https://filebelow.com/learn) ## About - [About FileBelow](https://filebelow.com/about) - [Privacy](https://filebelow.com/privacy) - [Terms](https://filebelow.com/terms) - [Contact](https://filebelow.com/contact) ## Limits worth stating - FileBelow cannot recover detail that was never captured. Enlarging an image spreads existing pixels; it does not add information. - A byte target and a minimum-dimension requirement can genuinely conflict. Where they do, FileBelow reports the dimensions that would work rather than silently violating one of the rules. - The quality figure shown on results is a structural-similarity estimate taken at a common on-screen size. It measures compression damage, not the change in resolution, and the interface says so. - Platform requirements change without notice. The linked official source is authoritative; this site records when it was last read. - PDF pages are embedded as JPEG. A screenshot converted to PDF becomes a JPEG of a screenshot. Lossless embedding is not implemented, and the tool says so. - Setting a DPI writes a header field. It changes no pixels and cannot make a print sharper. The DPI tool reports the pixel count a given print size genuinely requires rather than upscaling to fake it. - A file cannot honestly be made larger to satisfy a minimum file size. Padding it with meaningless bytes is the only way, and FileBelow does not do it. - Removing a watermark is possible for a determined person. A watermark raises the cost of casual reuse; it is not protection.