Large log files (already disabled Visualizer)

Hello there. I've been wondering why the logs exported to .mht files take so much disc space? Usually out tests last about 2 hours and the log files are 10-40 MB (that is already way too much in my opinion). Last night the tests went for about 7 hours and the report file couldn't be sent via e-mail because it was 2 GB large after zipping. I already disabled Visualizer in our tests.

What can I do to minimize the log files size? Is it normal that they take so much space? Is there any other way to export the log files? (so they don't take so much space)