JPG and JPEG: what is the difference
JPG and JPEG are one image format. The difference in the name of the extension does not mean a difference in quality.
Format and extension
The file photo.jpg and the file photo.jpeg can contain exactly the same data. Changing the extension between .jpg and .jpeg for a real JPEG does not re-encode the image itself.
When is it enough to rename a file
If the service requires it .JPEG, and you already have a real JPEG with an extension.JPG, you can change the extension using the file manager. Save a copy of the original and check that the extensions are displayed. Renaming a PNG or HEIC to .JPEG does not change their format.
When conversion is needed
HEIC, PNG, WebP or PDF require a real conversion. Our service issues a JPEG with an extension.jpg. Re-exporting an already finished JPG encodes it anew and may add losses.