I agree with djm79 (again, promise I’m not stalking ya). You don’t delete the image definition. When you need to update an image, you DEPLOY to proper hardware, make your updates, and then UPLOAD that computer and it overwrite the old version of the image.
Some things to note:
Make sure you prepare the computer before uploading the image. If you make tons of changes, it’s probably wise to defrag again and chksdsk /f
Remove from the domain before you upload.
An image that is being uploaded is stored in /images/dev/, and when complete, is moved to /images/imagename. So you’ll need enough storage available to hold the old image and the new image until the image is completely uploaded and FOG removes the old files and replaces with the new ones.