Setup Guide

Set as Default Image Viewer

Follow these steps to make Ultrafast your default image viewer on macOS.

1

Right-click any image file

In Finder, right-click (or Control-click) on any JPG, PNG, or other image file.

2

Select "Get Info"

From the context menu, choose "Get Info" (or press ⌘I).

3

Find "Open with" section

In the Info window, locate the "Open with:" section and click the dropdown menu.

4

Select Ultrafast Image Viewer

Choose "Ultrafast Image Viewer" from the list of applications.

Note: If you don't see Ultrafast in the list, click "Other..." and navigate to your Applications folder to select it manually.

5

Click "Change All..."

Click the "Change All..." button below the dropdown to apply this setting to all files of this type.

6

Confirm the change

macOS will ask you to confirm. Click "Continue" to set Ultrafast as the default viewer for this file type.

Important: "Always Open With" Bug

macOS has a known bug where the "Always Open With" option in the right-click menu doesn't work reliably. This is a macOS issue, not an Ultrafast issue.

Always use the "Get Info" method above to ensure your default app settings are properly saved.

Repeat for other image formats

To set Ultrafast as the default for all image types, repeat these steps for:

  • JPG/JPEG files
  • PNG files
  • GIF files
  • WebP files
  • HEIC files (iPhone photos)

Troubleshooting

Ultrafast doesn't appear in the "Open with" list

If Ultrafast doesn't show up in the dropdown:

  1. Click "Other..." at the bottom of the dropdown
  2. Navigate to your Applications folder
  3. Select "Ultrafast Image Viewer.app"
  4. Make sure "Always Open With" is checked
  5. Click "Add"

Changes don't stick / Files still open in Preview

This usually happens if you used the right-click "Always Open With" option instead of "Get Info". Try:

  1. Use the "Get Info" method described above
  2. Make sure you clicked "Change All..." not just changed the dropdown
  3. Restart Finder (Option + Right-click Finder icon → Relaunch)

Need to reset to Preview.app?

Follow the same steps above, but select "Preview" instead of Ultrafast in step 4.

All set?

Start viewing images at light speed. Double-click any image to launch Ultrafast.