The best image compressor for Mac
By Himanshu Ranjan · Updated 8 November 2026
ImageOptim is the best free image compressor for Mac: open source, drag and drop, lossless by default, and it strips metadata. FileDial is better when you need a file under a set size like 500 KB. Squoosh compresses in your browser without uploading, TinyPNG is a popular web service that uploads, and Preview works for one-off JPEGs.
How we chose: FileDial is our product, so read this list with that in mind. We chose picks for image compression from each vendor's own published information (product pages, pricing pages, support docs and privacy statements), checked on 2026-11-09, plus FileDial's own documented behavior. We did not lab-test every tool or run size or speed benchmarks on the others, so we quote no numbers for them. Order reflects fit for this search, not who made the app. Checked 2026-11-09.
1. ImageOptim
ImageOptim runs several optimization tools on each image and keeps the smallest result, removing bloated metadata such as EXIF, GPS position and embedded thumbnails. Its default mode preserves quality, with an optional lossy mode for smaller files. It needs macOS 11 or later and supports JPEG, PNG, SVG and animated GIF.
- Free and open source
- Lossless by default
- Strips GPS and other metadata
- Does not resize images
- No file-size target
- Optimizes files in place
2. FileDial
FileDial is our app. For photos, Compress › Compress makes a smaller copy that looks the same, and Compress under 2 MB, under 1 MB, under 500 KB, under 200 KB, Compress to size… and Compress by percentage… hit specific targets. Convert › Convert to WebP and Convert to AVIF give modern formats, and Compress › Optimize SVG cleans up vector files.
- Size-target presets
- New copy beside the original, with Undo
- Batch and watched folders
- Not free after the 1-day trial
- Needs macOS 14 or later on an Apple silicon Mac (M1 or newer)
3. Squoosh
Squoosh is a web app from Google Chrome Labs that shows the original and compressed image side by side as you change settings. Its project page says it does not send your image to a server; all compression happens locally in the browser. The site uses Google Analytics, which collects before and after image sizes.
- Compresses locally in the browser
- Side-by-side quality preview
- Many codecs to try
- One image at a time on the site
- Uses Google Analytics
4. TinyPNG
TinyPNG uses lossy compression on WebP, AVIF, JPEG and PNG files. Images are uploaded; the site says it retains them for a maximum of 48 hours before permanent deletion and that only the uploader can access them. A developer API gives 500 free compressions a month.
- Works on any platform
- Generous free tier
- API for developers
- Uploads your images
- Free tier capped at 5 MB per image
5. Preview (built into macOS)
Open the image, choose File > Export, pick JPEG and drag the quality slider down. You can export several images from one window. There is no size target and no metadata stripping.
- Already installed
- Quality slider
- Offline
- Guesswork to hit a size
- Keeps metadata
How we ranked these image compressors
People who search for an image compressor usually want web images that load faster, or photos small enough for an upload form or email. We weighed whether the tool keeps images on your Mac, whether it preserves quality, how it handles batches, and whether it can hit a specific size.
ImageOptim ranks first because it is free, open source, lossless by default and removes private metadata, which is ideal for websites and design work. FileDial is second because its size targets (under 500 KB, under 200 KB and so on) fit form uploads better than any slider. Squoosh is a great free learning and comparison tool, TinyPNG is convenient but uploads, and Preview is the no-install fallback.
Lossless versus lossy compression
Lossless compression rewrites the file more efficiently without changing a single pixel; savings are real but modest. Lossy compression throws away detail you are unlikely to notice, which gives much bigger savings. ImageOptim starts lossless and offers lossy as an option; TinyPNG is lossy; Squoosh lets you choose and compare.
Converting to a modern format can save more than any setting. WebP and AVIF are widely supported in current browsers. FileDial's Convert › Convert to WebP keeps animated GIFs animated but notes that metadata is not kept.
Metadata is part of the file size, and your privacy
Camera photos carry EXIF metadata such as camera model and, often, GPS coordinates. Stripping it saves a little space and avoids sharing where a photo was taken. ImageOptim removes it by default. In FileDial, Privacy › Remove location (a copy without GPS, pixels untouched) can run on the same batch, or in a recipe after compression.
Uploading versus compressing locally
TinyPNG states how long it keeps images, which is more than many sites do, and for public web graphics uploading may be fine. For personal photos, IDs or client work, local tools avoid the question. ImageOptim, FileDial and Preview run as Mac apps, and Squoosh runs in your browser without sending the image to a server.
Questions
What is the best free image compressor for Mac?
ImageOptim is the strongest free option. It is open source, works by drag and drop, is lossless by default with an optional lossy mode, and strips metadata such as GPS location. It handles JPEG, PNG, SVG and animated GIF but does not resize images.
How do I compress a photo to under 500 KB on a Mac?
Use a tool with a size target. In FileDial, select the photo and choose Compress › Compress under 500 KB. With Preview you can export as JPEG and lower the quality slider, but you will need to check the size and try again if it is still too big.
Is TinyPNG safe to use?
TinyPNG says uploaded images are kept for a maximum of 48 hours and then permanently deleted, and only the uploader can access them. It still means the image leaves your Mac. For private photos, local tools such as ImageOptim, FileDial or Squoosh avoid uploading.