• Instagram Profile Picture Size (Avatar Size): Must be at least 150×150 pixels

• Instagram Cover Photo Size: Must be at least 399 pixels wide and 150 pixels tall

  For profile pictures and cover photos with your logo or text, you may get a better result by using a PNG file.

• To get the best resolution, the recommended dimensions for Instagram photosare 1080 x 1080.
• Horizontal images: 1080 x 566.
• Video / Photo size for Instagram Stories: 750 x 1334.

Credit: https://postcron.com/en/blog/social-media-image-dimensions-sizes/