Upload image max 8 mo

Hi ,
And thank you for your help !

I have a question about upload size.
Like I am photograph, I want to sell my photos.
But of course my photos are very big (tiff files)
I want sell images to 25000 pixels wide and 800 mo – 1 go each one.

Is it possible to create a link to download the original file size ?

Thank you again !