For Mr. Welda and others...
There are several ways but this one always works.
You'll have to have p-bucket AND the MCM forum thread you want to put the photo in open in two browser windows simultaneously.
1) Bring up p-bucket and open the photo you want to load into your thread on the MCM forum.
2) On the right side there's a menu called "share links". Left-click on the "IMG" one. It will momentarily turn yellow, to let you know it's been copied. (Sometimes depending on your browser, who's been diddling with the p-bucket functionality, or the phase of the moon, you won't get the yellow flash. In that case you MAY have to right-click on the "IMG" address and copy it).
3) Go back to your thread page. Position the cursor where you want the photo to appear, and press "Ctrl-v" ("paste"). The photo address will come up in the thread window.
4) When you hit "post", the photo will appear.
OR.... If you're looking at thumbnails in a particular album, hover your cursor over the photo you want to put on MCM.
3 little white bars come up in the lower left corner of the thumbnail.
Hover over the bars and another menu opens above them in the thumb.
Left-click "share links"
A big white box will drop down with another menu on the right.
Left-click the "IMG" choice, which will flash yellow as above.
Same steps 3 and 4 as described above.
Nothin' hard about that.