For an error-free download, your photos should meet two conditions :
If both these conditions are met, the programme automatically optimises the quality and the size of your photos for faster display.
The format is indicated opposite "File type".
The size is indicated opposite "Size".
The size will be indicated in bytes : (b), KiloBytes : (Kb) or MegaBytes : (Mb)
The size should be less than 5 Mb
Before starting, don't forget to save your photos so that you can cancel changes in the event of a problem. The simplest way to do so is to use image editor. Image editors are software programs designed to modify images (framing, contrast, light, dimensions, special effects, etc...) They are often provided with your computer package, scanner, printer, etc... or they can be downloaded from the Internet.
You can reduce the dimensions of the photo or increase the compression rate to reduce the size of the file.