How to Convert Images on Mac Using Preview and Quick Actions
macOS includes several built-in tools for image conversion that most people never discover. Preview can export images in multiple formats with quality control. Finder Quick Actions can convert right from the desktop. And the sips command in Terminal handles batch conversions for power users.
Here are four methods for converting images on a Mac, from the most visual to the most powerful.
Step-by-Step Instructions
- Use Preview to export in a different format
Open the image in Preview. Go to File > Export. Choose your output format (JPEG, PNG, TIFF, or HEIC) from the Format dropdown. Adjust the quality slider for JPEG. Click Save.
- Use Finder Quick Actions for fast conversion
Right-click an image in Finder, hover over Quick Actions, and select 'Convert Image'. Choose your target format and size. This works on single files or selections of multiple files.
- Use the sips command for batch conversion
Open Terminal and run: sips -s format jpeg *.png --out ./converted/ to convert all PNG files in the current folder to JPEG. Sips handles HEIC, PNG, JPG, TIFF, and more.
- Use imageconvert.co for WebP and AVIF output
Preview and sips do not export to WebP. For modern web formats, use imageconvert.co in Safari. Drop your files and download WebP or convert from AVIF and other formats that Mac tools may not fully support.
Preview: The Hidden Power Tool
Preview is deceptively powerful for image conversion. The File > Export dialog lets you choose between JPEG, PNG, TIFF, and HEIC output. For JPEG, a quality slider controls compression. Holding the Option key while the Format dropdown is open reveals additional formats including JPEG-2000 and PDF.
Preview also supports batch export. Open multiple images (select all in Finder and open with Preview), go to Edit > Select All to select all images in Preview's sidebar, then File > Export Selected Images. Choose a destination folder, set the format, and Preview converts them all.
Finder Quick Actions: One-Click Conversion
macOS Monterey and later include a Convert Image Quick Action in Finder's context menu. Right-click one or more images, hover over Quick Actions, and select Convert Image. A dialog appears where you choose the output format (JPEG, PNG, or HEIC) and size (Small, Medium, Large, or Actual Size).
Quick Actions process multiple files simultaneously and save the converted files alongside the originals. This is the fastest method when you just need a quick format change without opening any application.
Terminal: sips for Power Users
The sips (Scriptable Image Processing System) command is a built-in macOS tool that handles image conversion, resizing, and metadata manipulation from the command line. For format conversion: sips -s format jpeg image.png converts a single PNG to JPEG. For batch conversion: sips -s format jpeg *.heic --out ./output/ converts all HEIC files in the current directory.
Sips supports JPEG, PNG, TIFF, HEIC, BMP, GIF, and PDF output. It does not support WebP, AVIF, or SVG rasterization. For those formats, use imageconvert.co or install third-party command-line tools like cwebp.
When to Use Browser-Based Conversion
Mac's built-in tools cover most format conversions but have gaps. They cannot output WebP, which is the preferred web image format. They cannot decode AVIF reliably in older macOS versions. And sips has limited control over compression settings compared to dedicated converters.
For WebP output, AVIF input on older Macs, or situations where you need precise quality control and visual before/after file size comparisons, imageconvert.co in Safari complements the built-in Mac tools.
Frequently Asked Questions
Can Preview on Mac convert HEIC files?
Yes. Preview opens HEIC files natively on modern macOS and can export them to JPEG, PNG, or TIFF via File > Export.
Does macOS support WebP conversion?
macOS can view WebP images but the built-in tools (Preview, sips, Quick Actions) cannot export to WebP. Use imageconvert.co or a third-party tool for WebP output.
How do I batch convert images on Mac?
Select multiple files in Finder, right-click, and use Quick Actions > Convert Image. Or use Preview's batch export. For command line automation, use the sips command.
What image formats does the Mac sips command support?
Sips supports JPEG, PNG, TIFF, HEIC, BMP, GIF, and PDF for output. It does not support WebP or AVIF.