You can delete a photo from your iMac computer the same way that you delete other files. Before deleting photos, make sure that you really want to discard them permanently. If you want to keep your photos but need to clear up some space on your computer, you can archive the photos before deleting them. To archive photos, copy the files to an external drive or save them to a CD or DVD.
Locate the pictures you want to delete. Double-click on the Finder icon, which looks like a smiling face. This will open a Finder window. You can click on folders within the Finder window until you find the correct folder and digital photo file, or you can search for photos by the file name or extension. On an iMac, your photo files are most likely in the folder named "Pictures." The extension on the end of each picture's file name is ".jpg" or ".jpeg."
Verify that you have found the photo you want to delete. Double-click on the digital photo's file name. Your iMac will open the file with your default photo viewing application. Look closely at the picture to make sure that it is the photo you want to delete. You may have several photos that are similar, such as a series of group photos.
Close the picture by clicking on the red "X" in the upper left of the photo, or select "File," then "Close" from the application menu. You will not be able to delete a picture while it is open.
Click on the digital picture file name or icon to highlight it. With your mouse, drag the file icon to the Trash (the wastepaper basket icon at the end of your dock). If you change your mind, you can open the Trash by double-clicking on the Trash icon. Drag the file out of the Trash folder, or highlight the file and select "File," then "Put Back" from the menu in the Trash window.
When you are sure that you want to delete all the pictures in the Trash permanently, go to your desktop and click "Finder," then "Empty Trash." Your iMac will display a warning message. Click "OK" in this message.
Things You'll Need
Apple computer with OS X installed
Digital photo files
When you delete pictures by emptying the trash, the photos can be recovered with data-recovery software. If you want to delete your pictures so that they cannot be recovered, go to your desktop and select "Finder," then "Secure Empty Trash."