If every time you post, you won't get any warning as long as you have some content. If you are adding in a single picture, add it in the OP, then post on your own thread with said picture. And don't worry too much about double posting on your own thread.
The rules for bumping are just
1. Must have sufficient content
2. A good amount of time has passed.
Condition one is a must-have, normally. Condition two can be done without content, but very sparingly. And "content" here just means something pertinent to the thread. You don't need a one thousand words post every single time you post.
And honestly speaking, every time you add an artwork, you are adding content, and it's not considered bumping per se.