Issue sending images saved from the web using Firefox app only

I like to download images from my phone to send in text messages. I can find images and save them/view them, but when I try to upload them to a text message an error message comes up stating that they are the wrong file type. This only happens with my Firefox app. The stock browser uploads and sends these images correctly. The one workaround I found is that if I were to crop the images saved from Firefox. The cropped image saves as the "correct" file type and can be sent. Any help on this? Thanks in advance!