Is there a way to list the pictures I've uploaded (as well as others have uploaded)? If not, how about adding it?

You mean the pictures uploaded with the thing that allows to put them in comments?
All uploaded pictures which are not used in comments are deleted after some time (I run the script which does that every one or two months).
So they should all be found in comments. From the Search page you can do a search on "[pic=" (with the square bracket) in comments to get such list then. If you search for "[pic=16872/" you should get only yours.

Is this still possible? Where has it to be written?

Go to the main page www.imcdb.org and click on 'Search'. Scroll down to the bottom and in the field 'Text to search:' type in [pic=18713/ You will get all comments where you have added a picture from the IMCDb upload system.

Thanks!
And I thus discovered that for having all your comments (with or without pictures), you have just to type your name in the "and/or posted by user:" field.

The strange thing is that you can edit or delete a comment, but not just see it in its page. The anchors for the comment are yet present (the "◊" gimmick, left to the date), in the pages?

You can also find all comments from a user (can be you) from the profile page of that user: there are links below the description entered by the user.

To go to the corresponding page from the comment search, you just have to click the page title in the left column (car model or movie title)...
The small lozenge link is available only on movie/car pages because it is allows you to get the link to paste it somewhere else (as direct link to a particular comment).
I could indeed add it on the search page for a more direct access in case that the target page contents a lot of comments.

That's what I meant: if a page contents a lot of comments, or even a few ones, you have to scroll to find the comment.
For example, it's better (in my world ) to go directly to this comment than to go to the corresponding page and then scroll to the comment (lot of pictures and lot of comments = "Scroll digit sprain" guaranteed ).