Interestingly, I was able to get some results by resizing the image i was trying to put in the databin to 320x200 - i think the images are getting nabbed by the 25k limitation but not returning the appropriate error message, however, from reading the documentation inserting images to Databins is supported and i've seen examples of it doing so (including Stephen Wolfram's blog!)

https://datadrop.wolframcloud.com/databin/DD957e678a3df-3478-414a-b2fe-4b4fcb1c1e43

Hi.

I'm sorry about the delay in responding to this. For quicker and official responses on potential issues you find, I recommend contacting support@wolfram.com. Developers and people sometimes don't catch things posted on online groups.

I was able to reproduce the problem and have forwarded it to the developer. My intuition is that "Image" isn't allowed for Databins, but the function should be giving a useful error message.