Drag and Drop

Error with hover text in drag and drop

I have a problem with hover texts. They don't show even when I hover my pointer on the image. Why is it necessary in my case? Because i'm developing content about solids, liquids and gas so I have to make it clear for example that I'm talking about the air in the balloon not the balloon itself.

Problems with images

I tried to incorporate different features with the "Column layout" in Moodle. For example the Drag and Drop feauture and the Multiple Choice feature. There I wanted to upload an image. This is really important, especially for the Drag and Drop feature. I have no problems uploading it, but other participants of the Moodle course can not see it. Why is this so and what can I do against it?

Thank you for your help!