Compression workflow
Meet an image or PDF upload-size target without guessing
A portal limit is a ceiling, not a quality setting. Start from a copy, identify whether dimensions or byte size matter, then reduce the least important information in measured passes.
Workflow
Record the real requirement
Note the accepted format, maximum bytes, pixel or page limits, and whether the destination reports decimal KB or binary KiB.
Reduce in controlled passes
For photos, lower quality gradually before shrinking dimensions; for scans, test moderate resolution and grayscale only when color is unnecessary.
Leave margin and test the destination
Aim below the stated ceiling, download once, reopen it, and upload the exact saved file to the real form before discarding alternatives.
Limits to understand
Lossy image compression cannot restore discarded detail, and a PDF containing fonts, vectors, forms, or already compressed scans may respond unpredictably. Repeated exports usually compound loss.
Privacy mode
The supported compression tools process selected bytes in the browser. The website still needs normal network requests for its page and code, so local processing does not mean the browser is offline.
Verify the result
Compare the reported output size with the saved file's properties, inspect faces and small text at 100%, reopen every PDF page, and retain the unmodified source until the destination accepts the copy.
Frequently asked questions
Why can a file under 100 KB still be rejected?
The service may use a different KB calculation, inspect dimensions or format, or add its own validation. Leave a margin and check every stated rule.
Is the smallest file always best?
No. Stop when the file passes its destination and remains readable; further reduction only removes useful information or resilience.