Practice a smaller attachment: Add the practice PNG to Image Compressor. Add Resize, choose Longest side and enter 600, then add Format and choose JPG. Compress and inspect the 600 × 400 result before downloading. Check the actual size rather than expecting a fixed saving; this simple illustration is much smaller than a detailed camera photo.
Practice file and tool: Download the synthetic practice file · Open the tool
How big does a photo need to be?
For viewing on a phone, tablet or laptop, 1,600 pixels on the long side is plenty; it fills a laptop screen and prints acceptably at postcard size. For photos someone might print at A4 or larger, keep 2,500–3,000 pixels. The full 4,000-plus pixels from a modern phone are only useful for large prints or heavy cropping later.
Pixel dimensions and quality do not guarantee a particular byte size. Check the total for the whole batch, including any ZIP or message overhead, against your account’s limit.
A batch in one pass
- Open the compressor and add up to 20 photos at once, or paste a screenshot straight from the clipboard.
- Add Resize and choose Longest side, for example 1600 px (or Pixels with both sides for a box). Images keep their proportions and are never enlarged unless you allow it.
- Choose JPG for ordinary photo attachments if the recipient may not open HEIC, AVIF or WebP. Keep PNG for screenshots with fine text or transparency; Original keeps the source format only where an output encoder supports it.
- Compress. The queue shows the before and after size of every file and the total saving.
- Download the ZIP and attach it, or download the files individually for a chat app.
If the recipient has a strict per-file limit — a form that wants each image under 1 MB — use Target size instead and let the tool find the quality that lands under the limit for each photo.
Email, chat and forms behave differently
- Email keeps exactly what you attach. Size it yourself, and consider a ZIP for more than a handful of pictures.
- WhatsApp, Messenger and similar apps recompress photos on send, often heavily. Sending a pre-sized 1,600-pixel JPG at quality 85 tends to survive their recompression better than a huge original. For originals, use the app’s “document” or “file” option.
- Web forms measure bytes. Use Target size and check the units in the form’s wording.
- Cloud links (Drive, iCloud, Dropbox) avoid the problem entirely for full-resolution sets; compress for the preview, share a link for the originals.
Screenshots and documents
Screenshots are usually PNG and can be surprisingly large. Try lossless PNG first. PNG → Smaller file — 256 colours (lossy) may reduce bytes further, but inspect small text, gradients and edges before using it. Photographed documents are better as JPG at quality 70–80 with the long side around 2,000 pixels — enough to read small print, small enough to send.
Quality settings that hold up
Balanced mode starts at quality 80; this is a setting, not a guaranteed reduction or quality threshold. If the pictures are for someone to look at on a phone, quality 70–75 is still fine and saves a little more. Go higher, 85–90, for photos that will be printed or where fine texture matters, such as fabric, hair or foliage.
WebP may give a smaller file at acceptable quality; compare outputs and only choose it when you know the recipient’s email client or app displays it; a picture that does not open is worse than one that took a second longer to download. When in doubt, JPG.
Before you hit send
- Check the total. The queue footer shows the combined size of all results; leave room below the sending and receiving accounts’ limits, which may differ.
- Open one or two results with Compare at 100% to make sure nothing important was softened.
- Rename if it helps the recipient: downloaded files keep their names with a -compressed suffix, so a batch is easy to tell apart from the originals.
- Keep your originals. Compressed copies are for sending; the full-resolution files stay on your device untouched.
Privacy note
Re-encoding a photo removes the embedded metadata such as camera model and, if it was stored, GPS location. That is a side effect, not a guarantee: images the tool leaves untouched because they were already small keep their metadata. If you need metadata removed for certain, check the file after downloading.