How much of the receipt is junk / advertisement? OR is the receipt too long or too wide? If the client wants specific data on the receipt then you need to know how to accommodate the receipt.
ex-------> the PO receipt is generally a long receipt. So after one has the itemized items showing, in between that and the cashier's ID is postal ads. Fold the receipt so the cashier's ID comes after the itemized total is complete. Now take a picture or scan.
ex2-------> the grocery store receipt has rewards and saving included on the receipt. Some receipts have a starting time(top of the receipt) and a finished transaction time (bottom) along with the cashier's name or ID. From the end of your transaction (itemized sales) is junk ads or rewards per shopping trip, that part can be folded or excluded from the "picture".
The Client is very much aware of what is on the receipt, so you are not trying to avoid "showing" them anything. An itemized receipt is what he wants to see-------->the store name, phone number, address, time, maybe the Cashier ID and required purchase if necessary. (How much was saved or earned is a mute point. It is on the receipt for your benefits not the clients.)
I don't know how to translate into MB, KB, or GB, but the picture I send in a report, no matter how long the original receipt is, is no bigger than a 2x3 wallet size photo.
I am not disagreeing with JPG, but this is how I do it.