People can’t resist sharing photos of their beloved pets on social networks, but most probably don’t understand how dangerous such a simple — and seemingly harmless — act can be. A pet photo can provide fraudsters and identity thieves with very valuable information.

What sensitive details could a criminal possibly glean from a pet photo, you ask? For starters, there’s the geolocation data that your smartphone embeds in the pictures you take by default. It’s a fairly simple task to sniff out GPS coordinates from EXIF (Exchangeable image file format) data.

Other information might be even easier to find. Your physical address and phone number, for example, which owners frequently have emblazoned on their pets’ tags. What’s meant to reunite lost pets with their owners can easily be misused by someone with a modest amount of skill.

You wouldn’t walk around telling complete strangers your phone number or address, yet that’s what posting a photo with a standard pet tag amounts to. It’s also far too common. Dell Cameron of the tech blog Gizmodo noted that a quick scroll through his Twitter feed turned up at least three offending images.