Function uploadTempImages

Upload temporary images into the current configuration. This should only be used for files which don't need to be persisted or aren't relevant for the finished configuration. Examples:

• When creating a PDF with screenshots of the 3d model, the images can be uploaded as temporary files, as they will be embedded in the PDF.
• The user can upload multiple images but he still has to apply them on the product in a second step. It's recommended to upload the images as temporary files and only upload them as cfgn files after they were actually applied.