In order for your customers to get the most value out of the items they purchase from you, we encourage you to follow the best practices listed below.
Most (if not all) of the PNG's you upload as assets to be sold in products should have transparent backgrounds. This allows the user to include the asset in a template with any color background, group elements together to create a larger design, etc.
High quality (300 DPI)
All of the assets you upload should be high quality images and should be 300 dpi in resolution.
Reasonable file size
All assets you upload should be a reasonable file size. Although we will optimize every image asset you upload to help reduce the file size (without reducing the quality), we recommend keeping file sizes under 10mb.
If your graphics consist of artwork that has been digitized (like watercolor painted elements), be sure any removing of backgrounds or artifacts has been done cleanly where the finished result is of professional quality.