1) click on My Forums near your name at top right of page.
2) Once you get to this next page, look for My Preferences in the header bar running across the upper center of the page. Click My Preferences.
3) here on this next page are settings for the way you will view the forum. The first part is titled my signature. Farther down is General Preferences, the second part of this page.
Here, in General Preferences, towards the bottom of that section, are some check boxes. One will say show photos that are part of posts. Check that one, then be sure to click at bottom where it says save, or submit changes.