Uploading images & storing them dynamically after resizing is a painless affair now using .NET, unlike what it used to be in Classic ASP. There are several good articles on uploading & resizing images on CodeProject (.NET Image Uploading [^], File Upload with ASP.NET [^], Thumbnail Image Creation and Image format Conversion Utility [^]) & elsewhere on the net (True Image Resizing [^]). One issue with resizing images is that the quality of the image deteriorates. This article is written in praise of the PNG image format & shows how the original quality of the uploaded image of any regular format can be maintained & even be improved.
PNG - What's it?
Check out this excellent article on the PNG image format - FAQ: Converting GIF or JPG to PNG [^]. To paraphrase the article -
- PNG stands for Portable Network Graphics and pronounced "ping".
- PNG is supported by the major browsers (Microsoft IE and Netscape 4.x and higher)
- The images are a lot clearer, no more grainy GIF images or pixelated JPGs!
This application allows the user to set the dimensions for the image to be resized & uploaded. The resized image is converted into the W3C Portable Network Graphics (PNG) image format by using the
PNG property of the
<%@ Page Language="C#" %>
<%@ import Namespace="System.Drawing.Imaging" %>
How to run the app
Unzip & run the .aspx file using IIS. Make sure a folder named PICS is created before-hand in the current working directory.
This article demonstrates how the quality of dynamically created images can be maintained & even enhanced by saving them in PNG format.