How to choose right image format?
AXPDF PDF to Image Converter helps you convert all formats of PDF files into commonly usable image formats, including JPG, TIFF, BMP, PNG, PCX, GIF, PS and EPS. Convert PDF into image documents with AXPDF, just so easy.
At some point or other you' d like to get different sizes of image files. This will occasionally happen when there' s need to email a friend a smaller sized image or when you' d like to keep an image because it looks beautiful. In most instances you will be reducing the size of the image or achieve high quality images.
Image file formats
The easiest way to tell if an image is big or small is to know the file format (file extension) first.
| Formats | File Size | Image Quality |
| JPEG | Small | Variable by adjusting compression level. Perfect for most images. |
| GIF | Small | Good. Useful for animation and image maps. |
| PNG | Normal | Good and useful for line art, text-heavy images. |
| TIFF | Normal | High, no image loss. Good choice for achieving important images. |
| BMP | Big | High quality with lossless data compression, and free of patents. |
| PCX | Big | High. PCX in letters stands for ‘Personal Computer Exchange' . |
| PS | Normal | Normal. PS in letters stands for postscript. |
| EPS | Normal | Normal. Useful for a preview picture. |
And then we find JPEG and GIF, small size of images:
| JPG: | JPG is the most commonly used image format by digital cameras for storing and transmitting photographic images on the Internet. It is small and is very popular today |
| GIF: | GIF is also widely used on Internet especially for animation and image maps. The image size is small and easy to carry through the Word Wide Web |
We can tell from the table above that usually BMP images have large file size, so does PCX .
| BMP: | We use BMP images a lot because it is widely used on Windows systems, we can simply edit it in Windows Paint and we have enough space on our hard disk to keep the BMP image |
| PCX: | PCX is not that widely used and we need to find viewers to view the PCX image |
Some medium size image formats:
| PNG: | PNG was designed for transferring images on the Internet. File size will be medium but as the same time, image quality is good |
| TIFF: | TIFF can save multi-page documents to a single file rather than a series of files for each scanned page. It is good choice for important image achieving |
| PS: | PS is using as a page description language in the electronic and desktop publishing areas |
| EPS: | EPS files are usually used for on-screen display |
Color depth:
Output color setting is available in converting formats of BMP, TIFF, PNG, JPG, GIF and PCX.
- If you choose to get a color image, the color depth is high and the converted image file size will be big. Gray image takes lower color depth and the black/white images take the lowest with small image file size.
- PostScript language level is available in converting formats of PS and EPS.
- The lower lever of the language is used, the smaller the size of the image will be created.
Compression ratio
For some of the image formats, there is no concept of the compression ratio. BMP is one kind of image formats that we know without compression. There are also types of image file compression techniques widely used in other image formats.
| JPEG: | You can set the image quality in AXPDF converter and the greater the quality it is settled, the less compression it is used and the bigger is the file size. |
| TIFF: | AXPDF converter provide different compression ratio for users to choose to convert.
File size: Small---------------------------------------------------------------------> Big Compression: Jpeg ----> FAX / RLE (monochrome) ----> LZW / PackBits ----> Default None |
| GIF: | GIF images are compressed using the Lempel-Ziv-Welch (LZW) lossless data compression technique. |
For other image formats, AXPDF uses default compression ratio or non-compression to convert.
In conclusion, choose the proper image format, the acceptable image resolution, the compression technique, and then you will get the proper image size you required of images generated from PDF files.