I have used InfranView for as long as I can remember as my image viewer (for Windows). When I started blogging in 2010 I used that to manipulate the images for my blog. The original photos from the camera are about 5MB and all I do is crop the bit of the photo I want (occasionally rotate it a bit as well) and resize to be 1024 pixel wide. This reduces the image to be about 300-500KB that I then upload. I have been doing this for so long I can whip though 10-20 photos for a blog post in minutes. If I need to do some simple markup such as a couple of labels or arrows I use InfranView. For detailed markups or lots of them I tend to then use Paint.Net as it is easier to manipulate the settings for better control and also has a better undo feature.