You don’t have to go to source view or do any manual searching. Just move your cursor into the image, and you’ll see the file in the link. Right-click on the name of the file in the link, and you’ll get a context menu.
- You can “Open link” and it will open the image in a pane. You can delete from the menu there.
- You can “Reveal file in navigation” which will show the file in your sidebar File Explorer pane. You can delete from there.
- You can “Show in system explorer”, which will open your computer’s file system. You can delete from there.
- You can just delete the link and leave the image in your vault. Then, there are community plugins which can detect and find unused attachments, and remove them. Discussion here: Remove unused attachments
(EDIT: Your screenshot looks like maybe mobile? I don’t know how relevant any of those ideas are in mobile, but I assume there are similar commands.)