Types and Uses of File Formats
There are many different file formats used within digital graphics including JPEG, GIF, TIFF, SVG, BMP, PNG etc. All of these file formats are used to store images of some kind. Some file formats are used to store bitmap images (JPEG, GIF, BMP etc.) while others are used to store vector images (SVG, CGM etc.).
There are also file formats for specific graphics programs such as PSD, AI, PSP etc. These file formats are specifically designed for certain programs such as PSD which is designed for Photoshop. This way, layers, effects etc can be saved within the file instead of just the graphic itself.
All file formats have limitations. Some file formats use lossy compression (JPEG) which takes up less space but reduces the images quality. Other file formats uses lossless compression (PNG) which keeps the full quality of the image but takes up more space. The amount of colours on an image also affects the size of the image e.g. an 8-bit colour image would be smaller but contain less colours than a 16-bit colour image. This is because there are less colours to choose from therefore the codes for each colour don't have to be as long which reduces file size. Most file formats let you choose the amount of colours which is usually 8, 16 or 32 bit.
All file formats have advantages depending on what the graphic is. In the case of graphics such as logos etc. JPEG is a very bad choice because it will add artifacts and smear text and lines. The best choice would be PNG because this is lossless compression and will produce the best image quality. In the case of photos, JPEG is a good option because it can have a lot of colours yet keep the image file small due to its compression method.
JPEG
Advantages
Small file size due to compression
Best for photographs
Disadvantages
Image data is discarded during compression
Handles sharp edges badly
PNG
Advantages
Loseless compression so no image data is lost
Can be 48-bit to create a true-colour image
Varying levels on transparency
Disadvantages
Some internet browsers don't have PNG support
No animation
Large file size
GIF
Advantages
Support transparency
Support animation
Disadvantages
Only has 8-bit colour depth
Large file size
Different File Sizes
All file formats will produce different file sizes due to compression methods, resolution and colour depth. File formats like JPEG are designed to create small file sizes by using lossy compression while file types like TIF are designed to create the best quality image possible by using big colour depths and lossless compression. The user can usually decide on compression and colour depth when saving so they can create a file size of optimal quality and size. For things like printing, TIF is definitely a better choice because it produces the best image but for website, JPEG is a better option because it doesn't take as long to download.
Vector graphics create generally small file sizes because it doesn't store data in a cell matrix but rather in mathermatical equations so the computer can recreate the file. There are lots of different types of vector file types that create different sizes because of the way they create the file.
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