How to Compress Images Under Target Submission Limits
Application portals, administrative forms, and customer support channels often enforce strict constraints on uploaded images, such as requiring each individual file to stay under 100 KB or limiting pixel dimensions to 1200 px.
This tool lets you configure exact per-file numerical ceilings for target size and pixel dimensions in advance, evaluate outputs in a side-by-side comparison, and adjust parameters to satisfy submission criteria.
Setting Individual Target Size, Long Edge, and Output Format
Files are not compressed immediately upon selection. You can queue up to 50 files (JPEG, PNG, WebP, or HEIC/HEIF) up to 30 MiB each, processing them in sequence.
- Target Size (KB): Set an integer between 1 and 5000 KB per file (calculated as 1 KB = 1,000 bytes; 100 KB = 100,000 bytes).
If an image cannot be compressed to this threshold, it is flagged as target unachieved.
- Max Long Edge (px): Select a preset (1280, 1920, 2560, 99999 px) or specify a custom integer from 1 to 99999 px. Note that 99999 px functions as a finite ceiling, not an infinite mode.
Upscaling is disabled. To satisfy strict file size caps, the engine may downscale output pixel dimensions below your chosen max long edge.
- Output Format: Choose JPEG, PNG, or WebP. JPEG does not support transparency (transparent areas turn opaque). While PNG and WebP accommodate alpha channels, re-encoding and resizing do not guarantee bit-exact pixel preservation and can increase file sizes for certain graphic assets.
Verification Example with Demo Image
Clicking "Load Verification Demo Image" when the queue is empty loads a test poster (2,526,322 bytes, 1200×800 px, containing fine typography, gradients, and granular patterns without personal data) and preconfigures JPEG output, a 100 KB target, and a 1200 px max long edge.
In verified PC browser testing conducted on October 23–24, 2026, executing compression produced:
- Result: 75,379 bytes / 976×650 px / image/jpeg
While the individual 100 KB limit was satisfied, canvas dimensions were automatically reduced from 1200×800 px to 976×650 px to meet the byte ceiling.
Output metrics will naturally vary depending on source characteristics and operating environments.
Side-by-Side Review and Adjustment Workflow
After processing, the original preview remains visible alongside the generated result, allowing direct comparison of visual quality, dimensions, byte sizes, output MIME types, and percentage changes.
You can save the output under a distinct filename for review. Modifying settings resets previous outputs while keeping registered source images intact, letting you re-run compression immediately with new parameters.
Page reloads clear memory permanently.
HEIC Handling, Metadata, and Privacy
- HEIC/HEIF Conversion: HEIC inputs are pre-converted in-browser into a quality 0.9 JPEG primary frame. The queue header calculates reductions against the actual uploaded HEIC byte size, whereas detailed comparison panels display the intermediate JPEG baseline.
Exif, HDR, and depth layers may not persist.
- Metadata: Retention or removal of Exif tags and color profiles is not guaranteed.
- Local Execution: All compression operates entirely within your browser runtime without transmitting image files to external processing servers.