Another alternative which is very inexpensive is to use an image hosting service. There are a number of free ones, and some which charge a minimal amount to host a picture for say a month. One I used to use occasionally is imagehosting.com which charged 25 cents to host a picture for 30 days.
One thing to be aware of in using those services is that some of them have rules regarding nudity and may remove your image if they discover it contains nudity. Always best to ask about it up front.
I haven't really checked out why your image is so small. I am assuming you are linking to the image you have in your GG portfolio. If that's indeed the case, I thought the allowed size was up to a maximum of 600 pixels on the long edge. I don't remember exactly what the file size limit was but my impression is that it was 80 or 90 kilobytes.
Anyway, welcome to GG and good luck sorting it out. The image below is in my GG portfolio and is 600 pixels high and about 90 KB.