What does the post-COS saving graph mean?

In the field of cosplay, the expression of "post-saved pictures" means that coser (role player) or post-retoucher constantly retouches and beautifies photos taken by others or himself in the process of post-processing photos, and accumulates a series of post-processed and remarkable pictures as examples to show his technical strength and portfolio. These "illustrations" can be used to display personal works, promote orders, improve skills and attract potential customers. By "saving drawings", the later retouchers can constantly improve their technical level and form a convincing case base of works.