Reduce Image Size

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.

How can you decrease image file size?

There are two ways how to reduce image size. Either you can compress the image, or lower its dimensions (width, height).

Compressed image files are less detailed with a decreased amount of pixels per inch. Images with lowered dimensions can maintain their good image quality but it will be harder for you to use these images for print.

The common downside of reducing the size of bitmap graphics is that images or photos will lose quality. They can often look blurry, less sharp, or small.

Why do reduce image size?

Photos taken from modern smartphone cameras have tens of megapixels and take a lot of disk space. This can be quite a headache if you don’t have a lot of free disk space on your HDD or memory card. Emails are too often limited in terms of attachment sizes. Because of this reducing image size is a good idea. In a lot of cases decreasing image size or resolution doesn't noticeably change the image quality. The photo still looks good even with 72 dpi or if its width and height are a bit decreased.