Thinspiration and fitspiration are classes of social media content characterised by idealised depictions of excessively thin and overtly fit/lean bodies, respectively. It is currently unknown whether and how exposure to thinspiration and fitspiration relates to symptom severity within high-risk clinical populations. Thus, in a clinical sample of individuals with eating disorders, we evaluated a model explaining how exposure to thinspiration and fitspiration relates to eating disorder symptoms. Individuals with self-reported eating disorders (N = 228, 47% with anorexia, 93% female) completed measures of image-centric social media use, thinspiration and fitspiration exposure, physical appearance comparisons, and symptom severity. Results showed that more frequent use of image-centric social media was associated with more frequent exposures to both thinspiration and fitspiration. In turn, these exposures were associated with more frequent physical appearance comparisons, and through these, greater symptom severity. Physical appearance comparisons mediated the relationships of both thinspiration and fitspiration exposure with symptom severity. Exposure to fitspiration was more common than exposure to thinspiration. However, thinspiration exposure evidenced stronger associations with symptom severity than fitspiration exposure. In conclusion, our model provides a useful account of how eating disorder symptoms relate to thinspiration and fitspiration exposure, and to image-centric social media more generally.