FlyerTalk Galleries is another photo sharing venue that is available. I don't really know much about the rules for posting there, but they support a lot of file formats (jpg, jpeg, gif, png, asx, asf, avi, mpg, mpeg, mp2, wmv, mov, qt, swf, mp4, rm, ram) and apparently images can be uploaded in a ZIP archive to create a gallery, among other methods.
The main page of a gallery has all the thumbnails. If you right click on one of those images and choose properties you'll get something like this:
http://gallery.flyertalk.com/gallery/albums/DCA-CBRthelongway/IMG_1623.thumb.jpg
The URL is the gallery name, the IMG_1623 part is the picture name and then there is the .thumb part and the .jpg part. In addition to ".thumb" there is also a ".sized" option that will give a larger image and one that is more conducive to viewing in a trip report.
So basically you can construct the path to the image that you want to embed by using the path to the gallery ([noparse]http://gallery.flyertalk.com/gallery/albums/DCA-CBRthelongway[noparse]) the image name (IMG_NNNN), .sized for a normal sized image and .jpg at the end. If you put all that together and paste it in the box that pops up when you click on the insert picture button it should work out for you. Obviously you'll need to change the picture file name depending on which one you want to show.
In this case, the image put inside the [I MG]...[/IMG] tags looks like this:
Pictures by, and instructions produced with the help of, [B]Fly'nAAgain[/B]