Yes, it's understandable and very common. On desktop, users will usually hover over an image to see available actions, so you can use discoverability techniques to display the save and delete actions on hover (usually with a scrim over the image for better visibility) or you can have a small bar displaying those actions at all times.
On mobile, since you don't have the chance to use
hover you will need to show the available actions at all time.
Please note that you can also use bulk delete or save options, which means you will need at least 3 actions (save, delete, select)
As for this:
The latest image that has changed, will be an active/current image. Is
there a trick to let users know that is their current image?
There are no "tricks". Simply say it: "current image is the latest one" (or whatever wording you want to use. This is known as the K.I.S.S principle (Keep It Simply Stupid): you don't need any tricks, just do things in the simplest possible way. You can also enhance its hierarchy with a border, but order should be enough for most people (and obviously, last changed image should be the top one)