Restoring Backups

Some months ago, I backed up my iPhone 7 on my computer (not a Mac). Some days later, I deleted some pictures which I actually needed, but I couldn't restore the old back-up on my iPhone 7. I've tried to restore that old backup on my iPhone 5s (which has the same storage capacity), but it always appears a message saying that my iPhone 5s doesn't have enough storage (which is impossible, since the storage of the two iPhones is the same).

Is it possible to restore pictures from the old backup (which is still in my iTunes), without restoring the whole backup on another device? Is there a trustworthy app that I can download?