Your digital camera will probably take photos at a minimum of 14 MP - that's 14 Mega Pixels and would allow you to print a fairly large photo at least 24" x 36" (610 mm x 910 mm) without any real problems...
Even my phone takes 8MP photos
Small problem - well it's a large one really as the file it produces will be very large certainly too big for you to send through your email which will probably curb you to 10 MB for any one email
Remember we are trying to print a greetings card that measures 145mm square so it does't need to be that big - 2MB is perfectly OK
If you have photo editing on your computer you can reduce the file size by altering the image size -
Do Not Alter The Dpi, which is likely to be set at 300
As always there are lots of ways around these small (large) problems
Make the files smaller or Send me multiple emails with a single photo on each one
You can use free transfer services on the web - I often use WeTransfer, which I find extremely good and it's free, which is nice
WeTransfer https://www.wetransfer.com
You could send me a CD with your photos on them
If you have problems or questions I am at the end of a phone - please call me...
You can send just about any format of file JPEG, PNG, TIFF - probably not RAW files as these are huge
Questions - please call or email - I am on your side
email : john@artistsofireland.com
telephone : 086 076 7970