Why is this raster image incorrectly used?
The picture above is my example of a raster image. As it should be obviously noted, this image is of poor quality due to the blurriness of the lines and letters shown. Presumably, this may have been a paper copied as a JPEG image since this file format is most commonly used in image scanning.
Going into further analysis, one can assume that someone had saved this image repeatedly (like through cropping) as a JPEG file which causes compression. As the image is compressed repeatedly, the file size becomes smaller and causes some details to erode (due to an increase of rectangular and square-like stretches of blurs; basically pixels that make up an image’s composition). Because of this, it is generally advised to only save an image once after cropping to minimize compression.
As this raster image could be printed or saved in a desktop folder, JPEG images are perhaps more suitable to use for the web as low-resolution RGB files store less memory and load up quickly on a web page; for printing purposes, JPEGs do not feature full detail, thus undermining their use here. And even with having any image saved on a computer regarding quality, it is advisable to do so under another format (such as TIFF) to avoid or lessen pixel compression entirely.