What TinyPNG actually limits
TinyPNG has been the default web compressor since 2014, and the underlying quantization engine is still excellent. The problem is not quality — it is the queue. The free web interface accepts up to 20 files at a time, each up to 5 MB. If you are optimizing a website with 200 product photos, you will be splitting your folder into ten batches, downloading ten ZIPs, and waiting on each upload round-trip.
The second limitation people run into is architectural. TinyPNG uploads every image to its servers, runs the quantization, and sends the result back. That is fine for a blog hero image. It is the wrong choice when the folder contains customer photos, scanned invoices, or anything you would not e-mail to a stranger.
The third limitation is the paid tier. The TinyPNG API removes the 20-file cap but charges by compression count, and the editor-tier subscription is aimed at developers, not at someone who just wants to shrink a folder once.
Comparison table
| Tool | Bulk upload | Per-file size cap | Formats | Offline / local | Files leave your device? |
|---|---|---|---|---|---|
| PixlReady | No limit; batch + ZIP download | No hard cap (limited by RAM) | JPG, PNG, WebP, GIF, BMP | Yes — runs in your browser | No |
| TinyPNG | 20 files per batch (free web) | 5 MB per file (free web) | PNG, JPG, WebP | No — server-side | Yes |
| Squoosh (Google) | Single file per window | No hard cap | JPG, PNG, WebP, AVIF | Yes — PWA, offline after first load | No |
| Compressor.io | Single file (free tier) | 10 MB per file | JPG, PNG, GIF, SVG | No — server-side | Yes |
| RIOT (desktop, Windows) | Batch via shell | No limit | JPG, PNG, GIF, BMP | Yes — native Windows app | No |
Which one should you pick?
Pick PixlReady if you have a folder to compress
PixlReady's batch compressor is built for exactly the TinyPNG workflow people hit the wall on: drag in a whole folder, watch the queue compress each image in the browser, and download a ZIP. There is no 20-file cap, no 5 MB cap, and no upload. For hitting an exact KB target (e.g. "get every product photo under 200 KB for the form"), the compress-to-KB mode uses binary search so each file lands on target in one pass.
Pick Squoosh if you are comparing codecs
Squoosh is a toy compared to a batch tool — it handles one image at a time — but the side-by-side before/after slider and the live codec comparison (JPEG vs WebP vs AVIF at the same quality) is unmatched if you are deciding which output format to standardize on for a website.
Pick RIOT if you are on Windows and want native batch
RIOT (Radical Image Optimization Tool) is a free Windows desktop app that previews the compression as you drag the quality slider and supports command-line batch. It is old-school, free, and completely offline.
Pick Compressor.io only for one-off small files
Compressor.io's lossy compression is solid, but the free tier is one file at a time and the server-side processing means your images leave your machine. It is fine for a single blog photo, weak for a folder.
How image compression actually works
Two families of compression matter here. Lossy codecs (JPEG, WebP lossy) throw away colour detail the eye does not easily see; they are the reason a 4 MB camera photo drops to 200 KB with little visible change. Lossless tools (PNG quantization, WebP lossless, GIF) shrink the file by re-encoding repeated patterns without removing any pixel data - smaller gains, but zero quality loss. TinyPNG's strength is its PNG quantization: it reduces the palette from millions of colours to a few hundred, which is why a 4 MB PNG logo collapses to 200 KB while staying crisp. For photos, JPEG or WebP lossy is the right weapon; for logos and screenshots, PNG quantization is.
WebP: why it is usually the default now
WebP compresses 25-35% smaller than a JPEG at the same visual quality, and supports transparency like PNG. Every current browser serves WebP. The practical rule: export a WebP for the live site, keep a JPG fallback for older browsers, and use PNG only for logos, icons and transparent cutouts. Converting a whole folder of JPEGs to WebP is one pass in the format converter; the bandwidth saving is immediate.
Hitting an exact KB target
Forms and upload portals frequently demand a specific size - "under 200 KB", "under 1 MB", "10 to 300 KB for the Indian passport portal". The naive approach is to guess the quality slider, export, check the file size, adjust, and repeat. The faster approach is a target-KB compressor that resizes the long edge and tunes the quality in a binary search until the output lands within a few KB of your goal, then you download the result. Always resize to the display dimensions first before crushing quality: a 4000 px photo squeezed to 50 KB will look blocky, while a 1200 px photo saved at medium quality at 50 KB looks clean.
Privacy: what you are actually sending to a server
When you upload a folder to a cloud compressor, those images are transferred, processed and (in many cases) logged or cached on a third-party server. That is the right trade for a public blog photo. It is the wrong trade for customer headshots, ID scans, contracts, unpublished product photography, or anything with a face and a name. A local browser compressor does the same work on your own machine, so the bytes never leave - which is also why there is no upload cap, no queue and no 20-file limit. The only thing you trade away is the convenience of opening any browser; in return you keep the folder private.
Common questions
What is the TinyPNG file limit?
The free TinyPNG web tool accepts up to 20 images at a time, each up to 5 MB. The paid Developer API removes the per-request count but still enforces file-size and bandwidth limits, and bills by the number of compressions.
Is there a TinyPNG alternative with no file limit?
Yes. Browser-based tools that compress locally, like PixlReady's batch compressor, have no per-batch file count and no per-file size cap beyond what your device's memory can handle, because nothing is uploaded to a server.
Does TinyPNG upload my images to their server?
Yes. TinyPNG's web tool uploads each image to its servers for optimization. That is fine for stock photos, but it is the wrong tool for customer photos, ID scans, or any image you would not send to a third party.
Which compressor keeps transparency in PNGs?
TinyPNG, Squoosh and PixlReady all preserve alpha transparency. Avoid tools that flatten to JPG as their default export, or you will lose the transparent background you spent time cutting out.