A Pinterest profile picture identifies the account. A profile cover introduces the wider visual world of a business. They have different jobs, and a miniature copy of the cover rarely makes a good avatar. Choose a portrait, a simple logo, or a compact mark that remains recognisable beside your account name.
This page prepares our 600×600 square export. That is a working preset, not an official claim about the size Pinterest requires or displays. Check the current profile editor for its accepted upload options. The useful test is whether the face or logo remains clear in the small places where the account appears.
If the business has a long name, use a compact identity designed for small use rather than shrinking the full wordmark until no one can read it. Leave space around the outer shape so rounded presentations do not clip the important parts. A clean silhouette and a deliberate background usually matter more than a very large file.