Under normal circumstances, A4 size paper with 300ppi resolution is enough for the book cover, and the picture of the material is as long as it is bigger, as long as it is not too small and fuzzy. Select the layer whose material needs to be adjusted. CtrlT can adjust the material size by selecting the material layer.

When designing a picture, the higher the resolution, the better, because it can be adjusted when printing, the larger resolution can be lowered, and the lower resolution cannot be raised. Considering the computer configuration and book cover size, 300ppi is enough, generally 72ppi is enough.

Extended data:

Resolution and pixel are two different units, and an image has four parameters: capacity, pixel, size and resolution:

1, capacity: refers to the storage space of the image file, that is, the size of the file, generally expressed in Kb and Mb.

2. Pixel: refers to the product or product expression of the width and height of a pixel, such as 3000×4000 or12 million.

3. Resolution: refers to the total number of pixels per unit length, representing the density of pixels, generally expressed in pixels/inch or pixels/cm.

4. Size: refers to the physical size of the printed image.