Explanation of image size and resolution
Bitmap images and photos are made up of pixels. Pixel is the basic unit of an image and its stores color information.
Image size - is the value represented by dimensions (width, height). Dimensions can be measured in pixels, points, millimeters, or inches.
Image resolution - is measured in pixels PPI (pixel per inch) or inches DPI (dot per inch). The higher the number of pixels per inch, the greater the resolution and image quality.
File size - of the image is measured in kilobytes, megabytes, or gigabytes. Images with higher resolution, image size, or bit depth are more detailed and takes more disk space. This is because they include more pixels in smaller images.