Image Slim
Compress, resize, convert, rotate and crop JPG, PNG and WebP files.
JPGPNGWebPAVIFHEIC
Compress PDF files
Shrink heavy PDFs, with the quality left entirely up to you. Up to 15 at a time, 25 MB each.
Compression optionsLossless
Presets
Cleanup
These pages are left exactly as they are — useful for a page that is already a small, sharp scan, or one you need to stay pixel-for-pixel exact. Everything else still compresses normally.
Drop your PDFs hereChoose your PDFs
or pick them from your computer — up to 15 at a time.
PDFMax 25 MB each
How it works
- Step 1
Drop your PDFs
Drag up to 15 PDFs onto the page, or browse for them. Each can be up to 25 MB. Anything else is refused straight away, with the reason.
- Step 2
Pick your quality
Starts at 100%, which re-encodes nothing. Lower it and every file shows its new size straight away — nothing is uploaded again, so you can compare settings freely.
- Step 3
Download what you need
Take PDFs one at a time, or grab the whole batch as a single zip. Files are removed from the server an hour later.
Where the savings come from
In a scanned or photo-heavy PDF almost all the weight is embedded images, so that is what the quality percentage controls — it is the size those images are scaled to, not a JPEG quality dial. Everything that makes the document readable and searchable is copied across untouched. At 100% nothing is re-encoded at all, which on an already tightly-packed PDF honestly saves very little; that is the trade the setting lets you make.
- 100%
- lossless — structure packed, duplicates merged, no pixel touched
- Below 100%
- images scaled to that percentage, mozjpeg quality 85
- Untouched
- text, fonts, vectors, links, page layout
- Skipped
- CCITT fax, JBIG2, CMYK, masked images
Why use SlimFile for this
Starts lossless
The default of 100% changes no pixels at all. You choose how far to go, and can change it per file.
Never bigger than before
If a PDF cannot be made smaller, the original comes back untouched — you never download a larger file.
Text stays text
Only embedded images are rebuilt. Fonts, links and selectable, searchable text are left exactly as they were.
Free, no sign-up
No account, no email address, no trial that runs out.
No watermark
What you download is clean — nothing added to your file.
Deleted within an hour
Uploads and results are removed automatically about an hour after processing. We never look inside them.
Questions
How do I make a PDF small enough to email?
Add the PDF and try 50% quality — on most scans and photo-heavy documents that roughly halves the file with no difference you can see at normal size. Many email services cap attachments at around 20–25 MB, so check the new size shown against that before sending.
Is it safe to compress a PDF online?
Here, the file is processed and then deleted automatically within about an hour, nobody looks inside it, and nothing is added to it — no watermark, no branding. Password-protected PDFs work too, and the password is used once and never stored.
How much smaller will my PDF get?
That depends on the quality setting and on what is inside the file. The default, 100%, changes no pixels at all, so it usually saves only a fraction of a percent — most PDFs are already packed tightly. Dropping to 50% typically takes half the size off. A PDF that is only text and vector graphics barely changes at any setting, because there is nothing in it to compress.
What does the quality percentage actually do?
It is the size the images inside the PDF are scaled to. 100% means nothing is re-encoded. 50% means each embedded image keeps half its width and height — for a typical scan or brochure export that is still around 300 DPI at A4, which is full print quality. Scale is used rather than a JPEG quality dial because images inside PDFs are usually already efficiently encoded, so lowering their quality saves very little before it starts to show.
Which setting should I pick?
Start at 100% if you cannot accept any change at all. If the saving is too small to be useful, try 50% — on most documents that halves the file with no difference you can see at normal viewing size. You can change the setting on each file after compressing and watch the size update, without uploading anything again.
Does the text stay selectable?
Yes. Text, fonts, vector graphics, links and page structure are left untouched. Only embedded raster images are rebuilt, so the document stays searchable and the text stays sharp at any zoom.
What exactly is changed?
Embedded JPEG and JPEG 2000 images are downsampled if they are larger than roughly 150 DPI at page size, then re-encoded at quality 72. That covers plain JPEG streams, the deflate-wrapped ones that Illustrator and InDesign export, and JPEG 2000 where the server can decode it. Images in formats that need their own decoder and carry more risk — CCITT fax and JBIG2 — are left exactly as they are rather than risked.
Some pages are one big image. Will the text still be sharp?
On screen, yes. When a whole page is a single scanned or exported image, its text is part of that image, so it is resampled along with everything else to about 150 DPI. That reads cleanly at normal size and at full-page zoom, but it will be slightly softer than the original if you zoom in far or send it to a printer. A PDF with real text in it is not affected at all.
Can you compress a password-protected PDF?
Yes. Drop the file in and enter its password when asked, and it unlocks and compresses like any other PDF. The password is used once to open the file and is never stored.
How many PDFs can I do at once?
Up to 15 files per batch, each up to 25 MB. Rewriting a PDF takes considerably more work than re-encoding a photo, which is why the batch is smaller than the image tool.
What if the PDF cannot be made smaller?
The original is handed back untouched and the row is marked "Already small". You will never receive a file larger than the one you uploaded.