How to Compress an Image to 100 KB (or 20 KB)

Hit 20 KB, 100 KB, or 500 KB upload limits for government forms and job portals. Resize first, then use FileShrinkr target file size presets for JPG, WEBP, or AVIF.

Published August 25, 2026 · Updated August 25, 2026

Why portals obsess over kilobytes

Online application systems often cap photo and signature uploads at 20 KB, 50 KB, 100 KB, or similar. Those limits exist because legacy stacks store documents in constrained databases and reject large binaries early. The error message rarely explains whether you failed on bytes, pixels, or format—so applicants bounce between random compressors until something sticks.

The reliable order is: (1) confirm official JPG/JPEG and width × height, (2) crop and resize to that box, (3) compress to the KB cap at the highest quality that still fits. Skipping resize and only lowering quality on a huge phone photo produces blurry faces that still miss the limit—or barely pass with ugly artifacts.

FileShrinkr’s target file size presets (20 KB, 100 KB, 500 KB) search for the highest quality under your ceiling for JPG, WEBP, and AVIF. PNG and PDF are not target-KB paths; use JPG for most forms.

Read the notification first

Copy the rules from the current year’s PDF or upload screen—not from a YouTube video filmed for a previous cycle. Note:

Maximum file size in KB
Exact or maximum width and height in pixels
Allowed formats (almost always JPG/JPEG)
Background or face rules that compression cannot fix

If the portal allows 100 KB, do not force 20 KB “to be safe” unless the face remains sharp. Extra headroom preserves eyes and text on nameplates.

Workflow on FileShrinkr

Open / and use the Image Editor to crop a passport-style frame and set the required pixels (or note them for the compressor).
Hand off with Compress This Image, or upload on the compressor tab.
Choose JPG, enter custom width and height if needed, and select the 100 KB (or 20 KB / 500 KB) target.
Prefer Server mode for HEIC sources, EXIF removal, or MozJPEG JPG.
Download and verify file properties: size in KB and dimensions must match the form before you pay the application fee.

For iPhone Camera Roll files, convert HEIC first—see HEIC to JPG. For SSC/UPSC-style checklists, see government exam photo resize.

What if the target cannot be reached?

Very large dimensions or noisy photos may not fit under 20 KB without heavy artifacts. FileShrinkr returns the closest result and can warn when the target was not met. Fix by reducing pixel dimensions first, simplifying the background (plain light walls compress better), or using a slightly higher allowed KB if the portal permits.

Signatures often need even smaller caps. Crop tightly around ink on white paper, then apply the 20 KB preset.

Browser vs server for KB targets

Target size search works in both client and server pipelines depending on format and options. PDF merge and some HEIC paths require the server. Browser mode keeps ordinary JPG/WEBP/AVIF/PNG work local when you do not need those features—useful on shared PCs when you prefer not to upload.

Email and WhatsApp are different

Email clients and chat apps also dislike large attachments, but they rarely publish a single “100 KB photo” rule. For email, moderate quality JPG or WEBP and sensible width (under ~1600 px) usually suffice—see prepare images for email. Form uploads are stricter: obey the stated KB and pixels exactly.