Can’t get the original size picture

[Chengzhi-EXT_GU]

I have a question about the size of the image uploaded from App,

In UX>Options>Forms, I have set the “Image upload size” to “Full”, according to the below explain,

the size will be the original size, but the size will always be compressed when uploaded.

Sometimes, the photo are even compressed to 50 KB, but I checked the photo in the mobile phone, the original size is about 5 MB.

How do I get the picture with the original size?