All AV products will work in roughly the same manner. What AVG is doing is not bad or wrong, bad input results in bad output which is what we are probably seeing here. Not worth throwing out the baby/bath water based on one false positive.

Start by marking the site as safe in the AVG settings. Then report it as a "good" site if you can. This should allow you to see it.

If a site gets reported as being a risk by a customer AVG then updates the central cloud database.
Some less experienced people may be worried about something and so hit the "report" button unknowingly.
If enough people report something AVG may then mark their database and so all users with AVG installed will see this change the next time they look the site up to connect to it. This is why only the AVG users are currently reporting it. Other AV software has not had the report and so is happy.

When your machine goes to connect to tm-img the AVG checks the site name (DNS or domain name services) with AVG cloud.
AVG reports it as suspect/bad etc and so your computer bocks it.

This means that people need to report it as good or through some feedback mechanism it needs to get corrected in their database.

For those of you who are non-technical - do not just load another AV program on top of AVG as this will cause melt-down. Removing AV software can be quite a challenge. AV software links very tightly into the operating system in order to do it's job and only one can exist at a time. Always fully remove the old one first. If you have Kaspersky start with prayer as it is a little devil to extract so be careful.

Everyone loves a Morgan. Even me, unless it's broken again.