Adding the sharpening filter increases the file size a small bit, but that action enhances the visible quality of the image and makes it sharper. Changing the quality does not change the file size that much, the default quality is 60, so decreasing to 40 did some, but it also affects the visible quality of the image. The largest decrease in file size, is when saving the image as JPEG. Lets see, part by part, how the file size decreases for each step in the way. Does it look good enough? Well, that will always depend on what you think, if its not good enough then increase the quality setting (and the file size) until you think its “good enough”. That is a reduction to 5% of the original file size and a much more pleasant file size to download. This all together reduces the file size to 26KB. It is sharpened to reduce the fuzziness introduced in the resizing process.
The above image is rescaled to a width of 630 pixels, saved in JPEG with a quality of 40. The original image is saved in PNG-format, 768 x 512 pixels and a file size (weight) of 557KB. Img.php?src=kodim07.png&w=630&save-as=jpg&sharpen&q=40įlowers, kodimg07.png, from The Kodak Colorset. Lets take the flower-image belov as an example. GIF and PNG 8-bit images can have max 256 colors. Using the parameter palette reduces the number of colors to max 256 colors. The parameter save-as can be used to save the target image as jpg, png or gif. The original image is 768 x 512 pixels with 72 079 colors and a weight of 534KB. Here are some examples when changing file format using kodim23.png as base. It is possible to change the target file format. Photo images are easy to resize but computer generated images, vector graphics and screenshots should not be resized. Use for photos and paintings or computer screen shots.Ĩ-bit, 24-bit and 32-bit per pixel including transparency, semi-transparency and lossless compression.įor computer generated graphics, drawings, images and screen shots.Īs a basic rule of thumb, use JPEG for photo-ish images and PNG for computer generated images and screenshots. Lossy compression meaning image looses information when saving it. Use for logos or image with solid areas of colors.ġ6.7 million colors. Supports animated images and transparency. File formatĨ bits per pixel, max 256 color. To understand image processing one need to know the basics on these file formats. The different image formats JPEG, PNG and GIF have each its pros and cons. This is not always easy to achieve, but lets review some basics for quality and file size aspect, basics that will take you a long way. So, one need to have a balance of good enough images and their file size. But having the greatest images means large file size which means that the web page till increase its load time. Too low quality means that the user gets to see low-quality images which leaves a bad impression of the website. But file size is related to the quality of the image. The file size for images should be small, as small can be.