Is it healthy for my business to increase my page fans with non real customers /fake ones ?

It is not the right decision to increase your fans with nonreal customers. fake customers are negatively affecting not only the results of reach but also the difficulty of identifying real customers, accordingly, you will not be able to run Ads with a "lookalike" option which is a vital feature that impacts the budget and waist the time

What is the correct photo size on Social media platforms ?

Facebook post image size : 1080 x 1080 pixels Facebook Event cover photo size: 1200 x 628 pixels Instagram post size : 1080 x 1080 pixels Instagram Story size: 1080 x 1920 pixels Instagram Reels size: 1080 x 1920 pixels Twitter profile photo size: 400 x 400 pixels Pinterest profile image size: 165 x 165 pixels Snapchat ads image size: 1080 x 1920 pixels