Supposedly, each time you are looking at your own Gallery, there should be a link to click on labeled "Upload Pictures".
well, that link went missing for me about a year ago and no amount of asking "where did it go" resulted in any help.
I would access my Gallery from the link at the top of the screen labeled "Photo Gallery" and sure enough, get a search box for me to find my albums.
Open one of those albums and no link to use to Upload Pictures. Frustrating to say the least.
Today, I discovered that if you will access your own Profile (from one of your posts, click on your name above the avatar. Click on View Public profile) and look down in the lower right corner of that Profile Page, there is a box named ALBUMS.
In the lower right corner of that box is a link named "Show All Albums"
I clicked on that link and got a full list of every album I have ever created. Wondered where some of them went, never could remember their names.
Opened several of those albums from that page and wonder of wonders, the "Upload Pictures" link is now available once again.
So, if you, like me, have not been able to upload pictures to the Gallery, give this hint a try.