You need to be very careful when deleting images in Aperture to avoid accidentally deleting an entire project rather than a selection of pictures.
To delete an image, or a series of images, you first select them, and then choose File > Delete Version. Alternately, you can choose Delete Master Image and All Versions to automatically take out all files related to the ones you have selected. Finally, you can also use the keyboard shortcut, Command-Delete to delete the images.
If you’re about to delete a master file, Aperture will warn you with a dialog box. If you’re deleting referenced files, it will give you the choice to move the original referenced files to the trash.
The potential for trouble stems from the fact that it can be difficult to overlook which pane in the Aperture window actually has focus at the time that you delete, and it’s easy to not pay attention to Aperture’s warning dialogs.
For example, consider this Aperture window:
It’s very easy to assume here that what is selected here is the sunset image. It’s being show in the Viewer pane, it has a selection rectangle around it in the Browser pane. However, what’s actually selected is the Project. You can tell because the project entry is slightly brighter than it would be if the Browser pane had focus.
In this figure, the lower project is selected, the upper one isn’t.
So, if you hit Command-Delete thinking that the images in the Viewer pane are about to be deleted, make sure to check to see if it’s actually the current Project that has focus.
Aperture tries to protect you from this mistake by presenting you with a dialog box that says “You’re about to delete a project.” However, this box looks a lot like the usual “you’re deleting an image” box, so it’s very easy to not pay close attention to it, and inadvertantly delete an entire project.
Remember, though, that when you delete an image - or a project full of images - Aperture moves those images into an Aperture folder inside the normal Finder trash can, so you can always fish them back out. You’ll lose all of your metadata and edits if you have to do this, but you’ll at least be able to get your images back.
And do I know all of this because I made this stupid mistake? Of COURSE not! Well, not on an especially large project…