I'm not sure how we'd know about a sexy pic unless we already clicked ("read") the post ... unless someone posted a followup with Subject "Sexy new pic! You look great! (kiss, kiss, kiss)". But there are occasional clues:
The paper clip means a hot link to a webpage - maybe worth a click as it might be useful and save me TWO clicks (Profile then Website or cut and paste non-embedded link).
Her own subject line might say "Pic inside", "New pics for you!", etc. Those might get more clicks.
Regulars here get to know someone's pattern. ALWAYS a great pic, NEVER any pics, always good info (personal info, stats, tour dates, times, rates), never any stats or info ('check my website for calendar, rates, etc.).
NOTE: Everyone knows that EOM means there is nothing in the body of the message but "eom"s get a lot of clicks!! In my case, I am sometimes on a slow connection so I automatically click the next post while finishing the current post. Or sometimes I'm focused on a sexy pic and click the next post before reading the "eom" on the subject line.
Sometimes I click on an ad post knowing I will NEVER follow up with a call for the same (paying attention elsewhere, click anyway) reason. (Her subject line mentions tour dates not good for me but I click anyway. It's someone I know is super-elite, ie, super-expensive, but I click anyway. It's someone I know isn't my type because I've visited her Profile and webpage 1000 times, but I click anyway.)
As DTlover said: too many variables