To reproduce...

A)

1. Create a new Page resource

2. In the editor upload an image and display it in the text of the page

3. save the resource + open and edit.

4. try to add the image to another place in the same resource picking it up in the Server Files area

5. you get "File exists" error

4a. there is no problem to copy-paste it in the editor, uploading it again, or picking it up from the Recent Files.

B)

1. Create a new Page resource

2. In the editor upload an image with .JPG extension (not .jpg) and display it in the text of the page

3. try to add it to another place.

3a. uploading it again to the same resource from your computer - you get "File exists" error

3b. it doesn't show up in the recent files nor in (after save/open/edit) server files area.

C)

1. Create a new Page resource

2. Rename a file in the Course Files (the course was upgraded from moodle 1.9) from *.JPG to *.jpg (without that it doesn't show up in the image File Picker)

3. In the editor pick it up from the Course Files area and display it in the text of the page

3a. It doesn't show up in the recent files.

4. try to add it to another place in the same resource by picking it up in the Course Files area or Server Files area.

5. you get "File exists" error