Your profile picture is the first and most instazoom important thing potential followers see when they visit your profile. Therefore, it must be professional, clean and clear. It should also be consistent across all your social media platforms to ensure people recognize you when they come across your accounts.
You should take plenty of photos before committing to a profile picture so you can choose the best one that fits your brand and personality. Don't be afraid to experiment with props, expressions and poses to find your ideal shot.
If you are looking for a more comprehensive resizer, you can try downloading QEK, which allows you to resize photos and videos on your device. This is available for free on the App Store and allows you to resize images from your computer or a USB storage device.