My job is to design websites.i need to display an image in larger and smaller size.is there any possibility to increase or decrease the size of the image programmatically without effecting the image clarity.
Yes, if it's a vector image or graphic; rasterised images will show loss of quality when you resize.
You can have two versions of each image (small & large) or also, you can have a high res image in the server and a program to resize and send it to the client if requested
It sounds to me like you need someting like ImageMagick (http://www.imagemagick.org/)
what is the purpose of this poll?
That is what I never understood...
:confused:
ImageMagick and other such libraries will alter an image dynamically on the server so as to present. However, it is woefully innefficient and spuriously drains server resources when used on a significant level or in multiple simultaneous iterations.
As far as resizing, vector always works best, as raster has hard-definition limitations. Though you can always resize down quite easily, without much loss of clarity, considering the size. Resizing a rasterized image up usually only lets you get one clear shot of the resized image, otherwise you would need to go in with an unsharp mask and (in worst-case scenarios) an adjustment layer with a blurured/soft-light overlay of the original to even out the artifacts/jaggies.
Of course, the higher resolution your original master has, the more flexibility you have in resizing...