To organize your uploads, simply create a dedicated album. Using drag & drop you can upload files to your album and, at any given time, you can select one of your images and paste them into your forum conversation.
If you want to make an album for your prints, a second one for your Ultimaker and third one dedicated to your print corner, you can. There are plenty of albums to go around!
You can also create a hidden forum for projects you don’t want to reveal to others just yet.