JPG vs JPEG vs PNG vs BMP vs GIF

Most of the time, JPEG (.jpg) is the best file type, since it creates high-quality pictures with small file sizes by compressing the data. It’s great for storing and sharing your pictures. If you need a very high level of visual quality (for example, if you’re printing 8-by-10-inch enlargements), you should save in TIFF (.tif) format or save your JPEG picture at the very lowest compression level available.

JPEG Advantages

• Most programs can display, open, and save JPEGs.
• JPEGs are great for e-mail because of their small file size.
• Because you can vary the amount of compression used to save a JPEG, you can control the file size and image quality.

JPEG Disadvantage

• JPEGs automatically compress your pictures when you save them, which reduces the visual quality by a small amount. If you use a high compression level, the image quality can be poor.

Each format has its pros and cons, but there are differences and specific times when a certain format should be used.

BMP - Bitmap. This was probably the first type of digital image format. It's most common in Windows environments. This is generally medium-high quality but produces larger file sizes. This format is ideal for icons and small images.

JPG, JPEG. Became popular with the invention of the digital camera. High quality images and huge compression allows for big resolutions but small file sizes. This is the most common image format, especially for photos.

GIF. This format was created mainly for Internet uses, mainly for its small file size. It's good for fast-loading web pages only.

PNG. Portable Networks Graphic. They best overall image format, especially for computer-generated graphics and files containing text and images having sharp transitions, but not as good as JPEGs for photos because of the larger file size. PNG is a better choice for storing photos that require a lot of editing, however, since JPEEG is "lossy" and PNG isn't.

Although not as compatible with the Windows operating systems (especially XP) as other formats, PNGs produce very high quality images with high resolution, but the biggest pro is that PNG's can handle transparency that JPEGs cannot. PNG is mainly used in MAC operating systems but can now be used in Windows Vista.

JPG and JPEG are the same file format, it's just that years ago there used to be a three letter extension limitations for files (hence HTM and HTML files).

JPEGs (or JPGs) are good for Photograph type images and will often (but not always) be smaller than a PNG of the same image and better quality than a GIF of the same image

GIFs are great for line drawings (images that are not photographs). They have a limited color palette and so are often smaller than JPG or PNG equivalents. GIFs also support transparency but JPEGs do not.

PNGs support variable (or alpha) transparency and so can be of a better quality than GIFs when transparency is important. With a photograph, a PNG will almost always be bigger (by quite a lot in most cases) than a JPEG but for simple images PNG can sometimes be smaller than both GIF and JPEG.

BMP are bitmap files, they are a big file size.

In terms of web design you will probably never see BMPs being used due to their large size.

Here are some links for more information:

choose the right image format
which format to use
which image format is best? (this is a great post from web supremo Jon Snook)

Same file, different format

.GIF – 140KB

.JPG – 186KB

.PNG – 421KB

.BMP – 550KB

No quality loss between different types. However, this was a simple image with only a few basic colours. For best quality, in general PNG and BMP are the best. However, BMP files are ginormous, so PNG is usually the best way to go especially since it supports transparency. However, JPG is the most commonly supported in web browsers and programs.

Taken from SuperUser...

BMP - Bitmap. This was probably the first type of digital image format that I can remember. Every picture on a computer seemed to be a BMP. In Windows XP the Paint program saves its images automatically in BMP, however now in Windows Vista images are saved to JPEG. BMP is the basis platform for many other file types.

JPG / JPEG - (Joint Photographic Experts Group) Jpeg format is used for colour photographs, or any pictures with many blends or gradients. It is not good with sharp edges and tends to blur them a bit. This format became popular with the invention of the digital camera. Most, if not all, digital cameras download photos to your computer as a Jpeg file. Obviously the digital camera manufacturers see the value in high quality images that ultimately take up less space.

GIF - (Graphics Interchange Format) Gif format is best used for text, line drawings, screenshots, cartoons, and animations. Gif is limited to a total number of 256 colours or less. It is commonly used for fast loading web pages. It also makes a great banner or logo for your webpage. Animated pictures are also saved in GIF format. For example, a flashing banner would be saved as a Gif file.

PNG - (Portable Networks Graphic) Apparently this is one of the best image formats, however it was not always compatible with all web browsers or image software. Now days it is the best image format to use for website. I use .png for logo's and screenshots.

A great interesting read for more information would be the Wikipedia page about image file formats

• GIF: low animations and banners.
• JPG: photos and big backgrounds.
• BMP: anything :-S
• PNG: everything else! Great transparencys, shadows... All you want in a image file.

Something not yet mentioned is that JP(E)G is better compression for photos and other graphics that every pixel changes color. If the graphic has a horizontal row with several pixels the same color, GIF is a better compression so things like photos should be smaller as JPGs and solid graphics (cartoons as mentioned) or any other drawing with sections of the same color will usually compress better as GIF.

PNG is newer and commonly found for photos but may work well in either case. BMP are usually huge by comparison, but at the same time they are lossless. Lossless means you end up with exactly what you started with. Lossy formats, such as JPG, reduce the size by lumping similar-colored pixels into the same value so there is some loss in quality, even set at 100%.

Edit: Forgot to mention that different images will be best in different formats. One may be smaller as a GIF and another as a JPG - it just depends on too much to say a definite answer for every case.