ID 268837 - Dragging a .JPG image into a tileable procedural layer does not work

Problem summary
Dragging a .JPG image into a tileable procedural layer does not work. 

Customer reported version
3.2v1
Customer reported platform
Linux 
Steps to reproduce

1) Create two images, .JPG and .jpg

2) Create a tileable procedural layer in the Mari layer stack

3) Drag and drop the images into the procedural layer

4) .JPG will not transfer across

Note: .jpg (uncapitalised) works as expected

Workaround
Drag the image into the image manager first and then dragged from there.

Reproduced by support
Win7 - 2.6v5, 3.1v3, 3.2v1
CentOS 6 - 3.1v1, 3.1v3, 3.2v1
Sierra 10.12 - 2.6v5, 3.2v1

Expected behaviour
The image should load as a procedural layer/

Actual behaviour
.JPG images do not load.