Generally I like to either drag/drop a picture from my laptop image in to a reply or new post but I've only seen that option on the ThumperTalk Forum and is convenient but l reduce the size of the pictures cus I'm a bit old school about file sizes.
IMO as i mentioned is really nice to be able to COPY IMAGE from a website, paste directly into a post as well as being able to re-size it.
Below a direct copy image and pasted 1.5MB image full size.

Same as above but resized in my reply.
This is direct full size, about 200KB and it is
Then there is also the option to change the thumbnail or full image once attached or inserted.
As Tom said large picture file size might only be an issue to over all forum performance if there were hundreds of members posting lots of pics but I saw the file size limited when I first attached a picture and the admins could always check with the forum hosting to get stats and set picture file size limit later if needed.
Not sure if any of this helps but I'm liking the new forum more and more now i just need to get the bikes out and ride cus its SPRING
