In the past week I got a bunch of obvious spam in my inbox. They all had a garbled subject line with numbers instead of letters, missing spaces and wrong capita

In the past week I got a bunch of obvious spam in my inbox. They all had a garbled subject line with numbers instead of letters, missing spaces and wrong capitalization, and the body was an image. It's crazy, how are they getting through? Maybe the filter gets thrown off by the unintelligible (to the machine, as a human can understand the meaning) subject line?