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Initurn

Compress images in bulk

Files never leave your device. All processing happens in your browser.

KB

Each image is compressed to land just under this size.

Compressed has no transparency, so see-through areas are filled with this colour.

How to convert Images to Compressed

  1. 1

    Select or drag in as many images as you like.

  2. 2

    Set your target size in KB.

  3. 3

    Each file is compressed in turn, then download them all.

The same size search as the fixed-target pages, but you choose the number and feed it a whole folder. Every image is compressed individually to land just under your target, which is the important part — a batch tool that applies one quality setting to everything produces wildly inconsistent file sizes, because what a given setting costs depends entirely on the picture.

Why local batch processing behaves differently

Upload-based bulk compressors have to move every file to a server and back, which is why they cap the number of files, limit the total size, and put you in a queue at busy times. None of that applies here. Your files are already on the device doing the work, so there is nothing to transfer and no queue to join.

The trade is that your own hardware sets the pace. A hundred images will take a while, and a phone will be slower than a laptop. Files are processed one after another rather than all at once — deliberately, because running many large images through canvas simultaneously is a reliable way to exhaust a browser tab’s memory and lose the whole batch.

Choosing a target

  • 100–200KB for website images. This is where page weight stops being a problem while quality stays high.
  • 300–500KB for photographs you want to keep looking good, such as an archive you are trimming down.
  • 50KB or below only when a form demands it. At that budget most photographs will be visibly degraded and many will be resized.
  • Whatever number the destination specifies, if something is imposing a limit on you.

What to expect from the results

Every file comes back close to but under your target, each having found its own quality setting. Simple images will have used a high one; detailed images a lower one. Where quality alone could not reach the target, the image will have been scaled down and the result says so, with the dimensions it settled on.

Files that were already smaller than the target are still re-encoded, which means they are recompressed. If a batch contains images that are already small, be aware you are spending a little quality for no size benefit on those.

Downloading a batch

Download all triggers each file in turn with a short pause between them, because browsers throttle or silently drop a burst of simultaneous downloads. Your browser may ask once for permission to download multiple files — allowing it lets the rest through. There is no zip, since building one would mean holding every result in memory at the same time, which is exactly what processing them sequentially avoids.

Everything runs in this tab. No file count limit, no total size cap, and nothing uploaded.

Questions about Images to Compressed

How many images can I compress at once?

There is no imposed limit. The practical ceiling is your own patience and device memory, since files are processed one after another on your machine rather than uploaded to a server.

Why are the files processed one at a time?

Running many large images through canvas simultaneously exhausts a browser tab’s memory and can lose the whole batch. Sequential processing is slower but finishes reliably.

Will every file be exactly my target size?

Each will be just under it, having found its own quality setting. That is the point of searching per file — one fixed quality setting produces wildly different sizes depending on the image.

What happens to files already smaller than the target?

They are still re-encoded, so they get recompressed for no size benefit. If your batch has a mix, be aware you are spending a little quality on the small ones.

Why do I have to allow multiple downloads?

Browsers ask before letting a page save several files, and throttle rapid bursts. Downloads are triggered one at a time with a pause between them; allowing the prompt lets the remainder through.

Can I get them as a zip?

No. Building a zip would require holding every finished image in memory simultaneously, which is precisely the memory pressure that sequential processing exists to avoid.

Are PNG files handled too?

Yes, and they come out as JPGs. PNG has no quality dial to search over, so hitting a size target means converting to a format that does. Transparency is filled with the colour you choose.