In the early days, we used a startup called BoxC (now defunct I think) and took a more hands-on approach to shipping. They would drop off at or ship their their completed products to BoxC shipping locations which then handles fulfillment.

The site actually functions as a marketplace now, and the independent sellers handle their own shipping methods.

What is the largest size possible (that can be shipped without an ordeal)?

Lynn Boggess, paints on large canvases (some over 4 ft x 4 ft) using cement trowels:

http://www.lynnboggess.com/

Obviously, that is probably unrealistic for shipping from China.

Also, I was interested in having some abstract paintings "copied", using some of the images from:

https://open_nsfw.gitlab.io/

The images are only 224pxx224px.

Would that be possible? The image resolution is not that big, but I would like something like 2 or 3 feet in length/width.

I'm interested in this as well. I'm not wholly familiar with the shipping process, but does the business rely on taking advantage of any shipping cost discrepancies?