Bad Web Design: ActiveXWritten by Richard Lowe
ActiveX uses an interesting method for enforcing security ... it doesn't. Well, that's not exactly true. What happens is when a web page requests an ActiveX control browser determines if that control is already loaded onto your system. If it is ActiveX control is executed. If not, user is asked if it is okay to install control. Additional information about where control came from and it's security implications is also included.
The theory behind this security model is user knows what's best for his system. In my humble opinion, this is pure hogwash (a stronger expletive came to mind but this is a family site). Is your average web surfer really knowledgeable enough to make a decision like this? Look at it this way, by installing an ActiveX control you are assuming it is secure, won't damage your system and is bug-free. You are basically trusting completely company which created control, developers and people distributing image.
Yes there are security certificates involved, but those are relatively easy to get. Also remember how many security problems have been reported involving ActiveX controls.
I don't know about you, but when I get that little box stating a site wants to install an ActiveX control, my first impulse is to hit NO box, quickly followed by BACK key. This may seem a bit paranoid, but I use my computer all day long and I depend upon it for business and pleasure. Why would I want to put it at any risk for some silly little ActiveX control? The web is a huge place and there are plenty of other sites to look at.
Graphics for the web: GIF FormatWritten by Richard Lowe
The GIF (Graphics Interchange Format) format was invented in 1987 by Compuserve to allow images to be displayed. This format allows for 256 colors (which was a lot at time), compression, interlacing and animation. It is a very powerful format, suitable for many different types of images.
Due to limited number of colors, GIF is primarily useful in images with a distinct separation of colors. A cartoon, for example, is ideal for GIF format.
When you save an image in GIF format, you have option to specify how many colors will be saved. By doing this you can decrease size of an image even further. All of tools which are available to optimize GIF images work by reducing number of colors to bare minimum. This can produce astounding results in size of finished file.
Unlike JPEG, GIF uses a non-lossy compression algorithm. This means that images do not loose bits when they are decompressed. In order to accomplish this, GIF uses a proprietary encoding/decoding scheme called LZW (Lempel Zev Welch). LZW is an excellent compression algorithm which typically results in very small files (in comparison to fully expanded BMP files).
This compression method is actually cause of a bit of controversy. As it turns out, LZW is owned by UniSys, and over past few years they have made some attempts to collect licensing fees for products which save in GIF format. These attempts have had mixed results, and has caused development of a new non-proprietary standard called PNG.