It's an AVG false positive. They happen regularly, often enough that you don't need to worry about reporting it to us or the Irfanview author... just to AVG after you confirm it's their problem with Virus Total. According to Virus Total, AVG currently lists it as clean. So it either was fixed in the current update (select to update again) or was just broken in the current update and Virus Total is using a working one from a few hours ago. https://www.virustotal.com/en/file/63840adbeec6e82ffaadebb73908de217f550...
It's an AVG false positive. They happen regularly, often enough that you don't need to worry about reporting it to us or the Irfanview author... just to AVG after you confirm it's their problem with Virus Total. According to Virus Total, AVG currently lists it as clean. So it either was fixed in the current update (select to update again) or was just broken in the current update and Virus Total is using a working one from a few hours ago.
https://www.virustotal.com/en/file/63840adbeec6e82ffaadebb73908de217f550...
For future reference:
https://portableapps.com/support#false_positive
Sometimes, the impossible can become possible, if you're awesome!
Thanks for getting back to me. I thought as much, just checking.