Programs such as FreeCommander create a checksum of the image so it doesn't matter what it's been renamed to (from recollection it can identify if an image has been resized). Bing.com search will find the same image - even when text etc has been added. I think duckduckgo.com and google.com do as well but I don't use either much. Have a search online for duplicate file detection. Regardless of filename, an uploaded file can be cross checked by file size even prior to a checksum being taken in a matter of seconds.
You're right, I didn't say that this kind of analysis is impossible. But you have to consider two points:
- This requires some resources, which for this type of site are unnecessary.
- The site does not have a gallery system, so the user can not use images already loaded (although it is possible). That is, imagine that you want to upload the Bitcoin logo. But, someone did it before you. If he does that level of control, you wouldn't be able to upload. So you were left without the ability to use the service. It didn't make sense, don't you think?
What I was meaning was if multiple copies are uploaded, then the original uploader (as well as anyone that follows) looses their ability to delete an image. (then again a user could just reupload all files as their own to lock images on the site)
Not exactly! I will always know which was the first image to be loaded. Unless both images are loaded at the same time.
Also, don't forget the following: the images uploaded to the site are intended for use in the forum. When you put that image here on the forum, anyone can take that link and reuse it in another post. If that happens, you must speak to moderation to have this post removed.
But imagine, that someone makes a copy of your image, loads it again on the site and then uses it here on the forum. So, if you contact me to indicate this situation, I know which of the two images was uploaded first, and I can delete the second one.
