NEW YORK (AP) _ The online photo websites of Rite Aid, CVS, Costco and Wal-Mart Canada remain offline in the wake of a possible data breach at the company that hosts all four sites.

The companies say their photo sites remain shut down as a precaution. All four sites are administered by Canada-based PNI Digital Media, which is owned by Staples Inc.

Late last week, Staples acknowledged that PNI was investigating a potential credit card data security issue, but wouldn't say how many companies or people could be affected.

All four companies say that their other websites aren't affected by the possible hacking.

Rite Aid says its customer credit card information isn't processed by PNI.