Good Morning Quick question. I am listing 3 posters individually and also listing them as a set of 3. I have one sku per poster design currently, should i generate a unique sku for the set of 3 too? Just wondering what is best practice? Wanting to keep it simple and easy...

Hi I am using Photoshop to rescale my work. I cant find any info on upload requirements. What settings should I save my work? PNG? JPEG? PDF? CMYK? sRGB? Newbie any help greatly appreciated 😊