fMRI promises to uncover the functional structure of the brain. I argue, however, that pictures of 'brain activity' associated with fMRI experiments are poor evidence for functional claims. These neuroimages present the results of null hypothesis significance tests performed on fMRI data. Significance tests alone cannot provide evidence about the functional structure of causally dense systems, including the brain. Instead, neuroimages should be seen as indicating regions where further data analysis is warranted. This additional analysis rarely involves simple significance testing, and so justified skepticism about neuroimages does not provide reason for skepticism about fMRI more generally.