In looking at what type of images your clients are sending, it looks like you’re mostly getting personal photos from people who do not / will not ever understand what it is that you need or why you need it. Essentially, your average non-graphics person, or most of the rest of the world.
This is the important thing to remember, people as a general rule will NOT admit to ignorance. If they don’t understand what you are asking, they generally will not ask for help. By telling them what you need and then giving them instructions on how to get it, you are giving them a way out without the back and forth and forcing them to admit it.
There are books worth of psychology behind this problem, so not something you can fix. But you can approach dealing with it differently.
I generally approach this type of problem with specifics. Instead of possibly risking a miscommunication from them not understanding or not using the same terms I am, I tell them what I need and give them a link to the best step-by-step instructions on exactly HOW to send me the files that I need.
For example, if I need packaged native indesign files, instead of saying I need supporting documents, fonts, photos, etc. I tell them that the best way is to use Indesign’s built in packaging tool, and give them a link to instructions on exactly how to use it.
The reason I give them links to instructions is because A) the sad truth is the general attention span these days is so short, if you put long detailed instructions in an email, most people will just skip it and get frustrated because they “don’t have time” to hassle with all that. B) there is generally someone out there who already wrote a how-to better than I could so why waste my time, and then the original author gets a hit on their site.
If it’s something like sending you a photo from their phone, from the screenshot you can generally tell what phone they are using, or at least what OS it’s from, so you could give them a link to something like “How to send a photo from your iPhone”. Most people actually have NO clue how to even find their photos in their phone, or how to access the menus to send them, but they know how to take a screenshot, and that the phone automatically pops up asking how they would like to send the screenshot, so they think that’s the only way to do it.
If it’s a photo that they have in Facebook or other social media. Odds are pretty good that they used the built in links and tools to upload the photo or directly took the picture there and have no idea how to get it back out. In that case, I would send them a link to instructions on how to do that from their phone or computer.
Hope that helps. Dealing with people so often becomes a lesson in psychology and essentially manipulation. The more you can understand the hidden subconscious things that govern most peoples behavior, the better you will understand how you need to communicate with them to work around that as efficiently as possible.