i have photos and i'm not sure if i have html enabled on the board (i think i do though) - try the features embedded in phpbb where you click on the img button after you've highlighted the photo link - that may help.
for example, if you had a photo (this won't work) at www.gadgetaddict.com/images/zrock.jpg
(you'd need the http://
in front anyway, you'd highlight the http:// www.gadgetaddict.com/images/zrock.jpg
and then click the img button - that should put [img] in front, and [/img] at the end of the highlighted section.
although, if you want to fiddle with the image size, then you'd have to use <img src=http:// blah blah...zrock.jpg width="100" height="100"> or whatever numbers...see? i do believe the img src= is pure html...