Why your image is still too big after compressing
When compression barely moves the number, the cause is almost always one of three things: the pixel dimensions are far larger than needed, the file is a PNG holding photographic content, or the image was already compressed and has little left to give. Fix dimensions first, pick the right format second, and only then reach for the quality slider in the ToolCrix Image Compressor.
Cause 1: dimensions, not quality, are the problem
File size scales with pixel count. A modern phone photo is often 4000+ pixels wide, but a blog column displays perhaps 800 of them — the rest is downloaded and thrown away. Dropping the quality slider on a full-resolution image fights the wrong battle: halving the width quarters the pixel count, which typically saves more than any quality setting can. Scale the image down to the largest size it will actually be displayed at, then compress the result.
Cause 2: a PNG doing a JPG's job
PNG stores every pixel losslessly, which suits flat-colour logos and UI graphics but is wasteful for photographs — a photographic PNG can be five to ten times heavier than a visually identical JPG. If your stubborn file ends in .png and contains a photo, converting the format will achieve what no amount of PNG optimisation can. The reverse also holds: JPG-ing a screenshot of text smears the letters with compression noise while saving little.
Cause 3: it's already been squeezed
Images downloaded from the web, exported from messaging apps, or saved from social media have usually been compressed once already. Re-compressing them yields small gains and stacks a second generation of loss on top of the first. If a pre-compressed image is still too big, changing its dimensions is the only lever with real headroom.
Why compressed images look blurry or blocky
Lossy compression discards detail the eye is least likely to miss — push it too far and the discards become visible. The tell-tale signs:
- Blocking — faint 8×8 squares in flat areas like skies, from aggressive JPG settings.
- Ringing — ghostly halos around text and sharp edges; the classic symptom of a screenshot saved as low-quality JPG.
- Banding — smooth gradients turning into visible stripes.
- Softness — overall blur caused by upscaling a too-small image, not by compression at all.
The remedy is to go back to the original and re-export: raise the quality a notch, or switch format. You cannot un-compress a damaged copy — artifacts only accumulate.
A launch-day workflow that prevents both problems
- Inventory your images and note where each appears (hero, inline, thumbnail).
- Resize per role — full-width heroes rarely need more than ~1920px; inline images ~800–1200px; thumbnails a few hundred.
- Assign formats — WebP or JPG for photos, PNG only for transparency and crisp graphics.
- Batch-process the resized set in one pass and grab the ZIP.
- Spot-check the risky cases (gradients, text overlays) at 100% zoom before uploading.
Frequently Asked Questions
Why did my image barely shrink when I compressed it?
It was probably already compressed, or it's a photographic PNG. Resize it, or convert PNG photos to JPG/WebP — those two moves free the most space.
Should I compress an image more than once?
Avoid it. Each lossy pass discards more detail. Keep an original master and derive every compressed copy from that.
What dimensions should web images be?
Match the largest display size: roughly 1600–1920px for full-width banners, 800–1200px for article images, and a few hundred pixels for thumbnails.
How do I fix an image that already has artifacts?
Re-export from the original at a higher quality. If the original is gone, artifacts are effectively permanent — smoothing filters just trade blockiness for blur.
Prepping a site launch? Batch-process everything in the Image Compressor, or browse more guides.