Stored Procedure - Swapping Out Missing Values

I've got a field that might have spurious values in it (say, an admin adds a new row but doesn't have an entry for this field). 

I'm trying to swap in the string no_image_EN.jpg if the value in the db does NOT end in .jpg. That way, any value rreturned is either a valid filename or no_image

I'm having trouble with the CASE statement, particularly testing just the last few cahracters of the string:

  select product_code,
CASE can_image_en
?? When (can_image_en LIKE '%.jpg') then can_image_en
Else 'no_image_EN.jpg'
End as can_image_en,
none of these do the trick either (some are bad syntax obviously):
? When (can_image_en LIKE '%.jpg') then can_image_en
? When LIKE '.jpg' then can_image_en
? When '%.jpg' then can_image_en
? When right(can_image_en,4) = '%.jpg' then can_image_en  This is the one that has correct syntax, though it seems to return false in ALL cases  CASE can_image_en
When '%.jpg%' then can_image_en
Else 'no_image_EN.jpg'