Knowing how to recognize the size of an image by the pixel can be an asset for modifying your images or cropping a video for example.
The pixel can be used to define the height and width of an image and its resolution.
The resolution will be expressed by the pixel by a metric or imperial value.
The pixel can allow you to resize an image, a website, a blog or a YouTube video for example that you want to integrate by iframe to a website.
From experience, if you want to integrate a favicon into your website, 75 X 75 pixels offers a backup file of less than 100mb, often a prerequisite.
340 X 340 pixels is a widely used image format. You will often find this standard format on download platforms.
Tip: Get your eye used to defining the pixel. It will surely be very useful in your projects.
In order to convert the format of your images, I recommend Gimp, a very powerful freeware.
https://www.ludovickinformatique.infos.st
