Bulk Image Compressor — Many Files at Once
Compress a whole batch of images in one pass — set a KB target or quality once, drop the folder in, download each compressed file.
One setting, a whole folder
Bulk compression is for the jobs where one image at a time is the bottleneck: a gallery’s worth of product photos, a shoot you need to email, a folder of scans that must all fit under a portal’s per-file limit. Drop the files in — drag a selection from Finder/Explorer, or pick many at once in the file dialog — and each one is decoded, compressed with the settings you chose, and given its own row with a before/after preview and a download link.
How the batch runs
Files are processed sequentially, not all at once — decoding twenty 24-megapixel photos simultaneously would eat gigabytes of memory, so the queue does one at a time and releases each image before starting the next. A status line under the controls keeps a running total: “12 images: 38.4 MB → 2.1 MB (−94%)”.
Change your mind about the settings? You don’t have to re-drop the files. Flip the mode, adjust the KB target or switch the format and the whole batch re-compresses with the new options — handy for finding the sweet spot between size and sharpness across a whole set at once.
Choosing settings for a batch
- For upload limits (per-file caps on portals): target-size mode, JPEG format, and the KB number from the error message.
- For web galleries: target-size or quality mode with WebP — smallest files, universally supported by browsers.
- For email or sharing: quality mode at 70–80% JPEG, or resize to 50% — halving dimensions cuts size roughly fourfold before compression even starts.
- Mixed inputs are fine: a PNG, a JPEG and a WebP in the same batch each get handled; pick “Same as input” to keep formats, or one format to normalize the set.
Per-file failures (an unreadable HEIC, a corrupt file) don’t stop the queue — that row is flagged and the rest continue. For single-file work with more explanation of the modes, see the main compressor or the target-KB guide.
Frequently asked questions
Is there a limit to how many images I can compress at once?
No hard limit — files are processed one at a time inside your browser, so memory stays flat even with a large batch. Practically, a few hundred photos per pass is comfortable; beyond that, splitting the batch keeps the download step manageable.
Can I download all the results as one ZIP?
Not currently — each result row has its own download link, which keeps everything on-device (there's no server to build a ZIP on). Your browser may ask permission to download multiple files; allow it once and the rest flow through.
Do the settings apply to every image in the batch?
Yes — one set of options (mode, target KB, format, resize) applies to the whole queue. If you change an option after the batch finishes, every queued file is re-compressed with the new settings automatically.
Why did one file in my batch fail?
The row tells you: usually it's a format the browser can't decode (HEIC from an iPhone, a TIFF, a BMP). Convert that file separately — JPEG/PNG/WebP inputs are supported — or on an iPhone, switch the camera to "Most Compatible" so new shots save as JPEG.
Is bulk compression safe for sensitive photos?
Safer than any upload-based service: the files are read by JavaScript in this tab and never transmitted anywhere. Batch of ID documents, property photos or client work — none of it leaves the machine you're sitting at. See the privacy policy.