When you send a screenshot (even if height/width only is cropped) , the screenshot’s width and height can be used to find the iPhone model of someone or narrowed down.
The most unique sized iPhone on the market right now is the iPhone 16 Pro and iPhone 16 Pro Max, as no other phone has the same width and height. So if you send a screenshot people will 100% know your exact phone. The regular iPhone 16 is common with the rest of the other phones and not unique.
If you send a screenshot from a iPhone XR, people can know if you using an iPhone 11 or iPhone XR since they have the same dimension which narrows down alot of options. (828x1792)
You can use this site here to view a list of all the dimensions. Click the iPhone’s tab and sort the physical width or height.
If you don’t want to expose your phone model, crop both width and height of each screenshot randomly. I would suggest cropping out the top of the phone as it shows your time if you care about that. Some sites like X have random inaccurate dimensions in uploaded screenshots, which is different from the original raw screenshot.
I haven’t really checked with android phones, but it’s probably the same thing.
A good example to “play” with could be https://coveryourtracks.eff.org/ which does highlight the idea of “bits of identifying information” namely :
“A “bit” is a basic unit of information for computers. The bit represents a logical state with one of two possible values, often represented as “1” or “0”, for example. In your results from Cover Your Tracks, some metrics may be listed as “1” or “0”, or “true” or “false”, indicating whether a setting is enabled or disabled. While each individual metric’s details may seem like a small amount of information, when combined with your browser’s other metrics, they can uniquely identify your browser. Your results are measured in “bits of identifying information,” which is a combined summary of all these metrics.”
Point being, not all behaviors, conscious or not, explicit or not, lead to the same amount of bits. Some are VERY valuable, others are basically pointless. Knowing the difference means not spending a lot of energy fighting without making a difference.