HOW TO Convert image formats

1 Choose your images

Locate the images you want to convert in the Finder and ç-click on each one. Once you’ve selected them all, if Preview is the default app for opening them, double-click. If not, ≈-click and choose Open With > Preview.

2 Select images in Preview

Click the sidebar icon in the Preview toolbar, or the View menu, and choose Thumbnails. Click in the sidebar, but not on an image, and then click ⌘+A to select all the images you have just opened.

3 Convert file format

With the thumbnails selected, click the File menu and choose Export Selected Images. Navigate to the folder where you want to export the converted images and click the Options button.

4 Set parameters

Click the Format menu to choose a file format for the exported images. Then use the Quality slider to choose the image quality. Note that the file size changes as you move the slider. When ready, click Choose to export.

5 Batch resize images

Follow steps 1 and 2 to choose images and select them in Preview. Click the Tools menu and choose Adjust Size. Choose dimensions from the ‘Fit into’ menu, or choose Custom to set your own. Set the resolution and click OK.

6 Rotate or flip images

Some other options in the Tools menu can be performed on batches of images. You can’t adjust the colour or annotate batches, but you can choose the Rotate or Flip commands to perform those actions on multiple images.