This still eludes me how some people may estimate Diggler at 8-8.25" based on that measurement pic.
I do agree that he may seem smaller on other pics but that's beside the point. Judging solely on this material, which appears to me to be legit until proven fake, I would make the following analysis :
1/ This is a side measurement for sure. However it is of good quality and we can clearly see that the NBP start of his penis would be around the 1" mark (even a little less to be fair, if we take the public bone (with its fat pad) as a reference and not the shaft itself).
2/ Likewise we can see the end of his johnson is around the 10,25" mark, which gives us a baseline length of ~9.25" nbp
3/ It is unclear whether the ruler sticks to the side of his shaft all along or if there is some angle, but let's assume there is some (this is a porn measurement after all..). I doubt it might exceed 15 deg honestly, which would give us (using basic trigo) a real length of : L = 9.25 * cos(15) = 8.93" nbp
Apply a reasonable safety factor to that, that is still difficult to see him at less then 8.75" nbp, which is basically Mandingo's size at his best.
Tbh this appears to me as one of the fairest "monster cock" measurements pics at our disposal, alongside the Miro's one.