When the JPG Compressor seems to misbehave, the cause is usually one of two things: something stopped the tool from running, or it ran but the result is not usable. This guide starts with the fastest checks, then walks through the common problems and exact fixes.
Quick Checks First
- Refresh the page - a stalled session is the most common cause of nothing happening.
- Confirm the input is not empty and actually contains what you meant to submit.
- Try the smallest possible input; if that works, the issue is size, not the tool.
- Turn off browser extensions that block scripts, then reload and test again.
- Update or switch browsers if the problem repeats across sessions.
Common Problems and How to Fix Them
The file barely shrank
Raise the compression aggressiveness or downscale - weight is pixels times quality.
Blocky artefacts appeared
Quality is too low for the content - step up a few points and recompress from the original.
Edges look like they have halos
Signs of over-compression - start again from the source at a gentler setting.
Skin tones band
Flat gradients suffer first - keep quality 85 or above for portraits.
I compressed three generations deep
Each pass stacks loss - always keep one untouched original and compress once from it.
Weight is still over the limit
Resize down to the display dimensions, then compress - that combination solves almost every limit.
When It Works but the Output Is Poor
If the tool runs fine but the result misses, the problem is almost always the brief, not the software:
- Compressing an already compressed copy
- Choosing maximum quality and keeping the weight
- Crushing low-quality sources into artefacts
- Ignoring dimensions when files are huge
How to Stop It Happening Next Time
- Keep a saved prompt template for every task you repeat.
- Change one setting per generation so causes stay obvious.
- Run a two-minute sanity test with known input after any update.
- Note every failure and its fix; a short troubleshooting log pays for itself.
Still Stuck?
Reproduce the problem with the smallest possible input and note the exact steps that triggered it. A one-line description of what you did, what you expected and what happened is enough to get a precise answer from support or a colleague.
Frequently Asked Questions
How much weight can I save?
Usually 60-90 percent at quality 80-85 with no visible change at normal viewing size.
What quality setting is best for photos?
82-85 is the sweet spot for most photographs; go higher for prints and lower for thumbnails.
Is JPG compression lossy?
Yes - detail is discarded. Keep an original for future edits.
Are my files uploaded?
No - compression runs locally in your browser.
Related Guides
- JPG Compressor - free online tool
- How to Use JPG Compressor
- What Is a JPG Compressor and How Does It Work?
- JPG Compressor Examples: Real Scenarios and Results
- JPG Compressor for Photographers and Bloggers
- Best JPG Compressor Alternatives Worth Trying
- JPG Compressor Tips and Best Practices
- Is JPG Compressor Safe? Free vs Paid
- More JPG tools and guides