here is a visual representation
open download location. eg in my case lets change index_5.php iwe 1ndex_5.jpg as shown
next long press on the file hadi uone the following options. depends on your file manager app. for me natumia Es file explorer. select rename
delete the php n change it to jpg or jpeg ama png ama any image file format supported by phone
*************
,,,,
utaona the file humo ndani.
now open it with a gallery app of your choice
.... hope umesaidika sasa
@benja