Feature request: allow user to delete the image they uploaded on the Create New Instrument page

[JoyfulGen]

If a user has uploaded the wrong image to the Create New Instrument page and they want to change that before clicking on Create Instrument and publishing the page, there's no obvious way to do so. I've found that if I click on Browse again and select another image, that new image automatically replaces the old one. But I think it would be more intuitive to do one of these things:

• Add a Delete button next to the image;
• Once an image has been selected, change the Browse button to Select a different image;
• Don't change any buttons, but just add a little text that says "To select a different image, click on Browse again."