Is there a trick to upload a profile photo?
Yes, there is.
You have to go to your control panel, and go to 'Edit Avatar Settings'
There, in the field "Enter a URL to an online avatar image", if you enter an url to an image of yours, it will appear in all your posts, althoug in a 90x90 size. That requires of course that you have a personal site to upload an image of yours, and that the url leading to that image is understood by the system. I say this because I tried urls to pictures to attachments on posts of this site, and they do not work, but urls to pictures on my site, work OK.
Manuel