A Salesforce specific Rich Text Field (I say Salesforce specific, because the RTF built in to Salesforce utilizes the Salesforce HTML editor so is assumed to have specific functionality pertaining to the Salesforce framework source) in one of our organizations forms allows me to copy and paste images of varying sizes directly in from memory. I can do this on both Chrome and IE 11, both are currently updated to their latest versions - valid 14/06/2016.
I can do this with 5MB pictures and it will compress them to 1MB, or I can do it with < 1MB images. Size does not present an issue.
I've had complaints from numerous users who can't use the C+P functionality utilizing the Chrome browser. They also report that they can C+P in IE but it never actually presents itself and the loading icon spins out "forever" without any result (so they can't actually do it in IE).
I asked one of the users to reset chrome to factory defaults and test and he still couldn't do it.
Thoughts much appreciated.
PS To those who marked this as being too generalized, in turn directing me to Stack Overflow, please let me know how you justify this as not being Salesforce specific. I'm happy to be wrong by the way!