The speed at which a website loads is a factor in search engine optimization that is growing in importance. Consumers do not want to wait even longer than a few seconds for a website to finish loading so that they can browse it. One of the main factors in how quickly or slowly a website loads is the number, type, and size of the pictures included on each page.

Deciding on what type of image to use for a new page or blog post can be especially difficult for the average small business owner or blogger. However, it is also important to use the correct types of images so that they do not slow down the speed of the site overall and negatively impact readers’ experiences on the site. There are five image formats that we will look at in this article.

PNG File

The .png file is an open-source that seems to be replacing .gif files in terms of small size and brands, as it is one of the best file types for web use. It supports 16.7 million colors, and 8-bit transparency. The main drawback is that large images will end up as a larger file size with .png than with .jpg files, and some older browsers do not support .png files.

SVG File

The final image size we’ll look at is .svg, also known as Scalable Vector Graphics. This allows users to create graphics directly through code, and shapes can be defined such as circles 150×150 pixels in size, with borders and fill colors. These files can also be scripted with Javascript, or marked up through the use of CSS. Svg cuts also result in smaller file sizes than other formats, although they can also be more complicated, and they are not supported in all internet browsers.

BMP File

The first is the .bmp file, also known as a Bitmap. These images are a Microsoft Windows file format. Because of the large number of people that use Internet Explorer and Microsoft Windows, .bmp files are scattered throughout the web. They are good for displaying photos with a lot of detail, as they support 16.7 million colors. The downside is that they end up as very large files sometimes, and there are better alternatives available.

JPG File

For photographs, a .jpg file may be more appropriate. In fact, .jpg (or .jpeg) files are a compression format, with the actual image a .jfif file. These types of files also support 16.7 million colors, although they do it in a smaller file format than a bitmap. However, the downside to this type of file is that compressing the image may cause it to drop in quality, especially if the same .jpg is compressed and saved over and over again.

GIF Files

For many images such as logos, a.gif file is probably the best choice. These use lossless compression, which means that the image quality does not suffer when compressed. On the other hand, only 256 colors are supported, meaning that more detailed images will be degraded. Thus, simple images like website brands or logos can be saved as .gif files, which result in small file sizes and no reduction in quality. More detailed images should use a different format. One additional use for .gif files is to create moving images.

Thus, each file format has its users. For images, a .jpg file is most appropriate. For company logos, the .png is becoming more and more popular, especially with its transparency uses. Small moving images are often much simpler with a .gif file, rather than creating a video.