When I was photographing my Zombicide figures I knew that I'd be asked for a size comparison photo. So I took one with the four zombie types from the Zombicide board-game alongside survivor types from an assortment of figure companies. If you are wondering about the Zombicide survivors, they are the same size as the zombie Walker. Do bear in mind that the Zombicide figures are not mounted on circular plastic slottabases so they appear to be a couple of millimetres smaller than the others.
Copplestone Castings Dark Future Militia Trooper, or as we all know him - Vampifan.
Zombicide zombie Walker.
Foundry Figures Wrecking Crew gang member with crowbar.
Zombicide zombie Fattie.
Hasslefree Adventurer - Grant
Zombicide zombie Runner.
RAFM USX Survivor - Hanna, or as I call her, Hannah Vaughn.
Zombicide zombie Abomination.
Studio Miniatures Survivor - Ohio.
I think you'll agree that they match up well with all of the figures I've featured. This photo also gives you a good indication of just how tall the Abomination is.
What I did not anticipate were requests for a group shot of all of my Zombicide figures. The best I can do is show you this in game shot from one of the (many) scenarios that Mathyoo and I played.