Why Save Images as .bmp?

Question

Just looking at all my project folders, we have hundreds and
hundreds of screen captures that are .bmp format.
I did my own test saving the same screen capture in different
formats - .bmp, .jpg, and .gif.
Results: .bmp is 955 KB, .jpg is 76 KB, and .gif is only 18
KB.
With all these images being published to our server, I was
thinking it must be important to optimize images or else I would
think this could affect how quickly the pages load once online.
As a general rule, shouldn't all the screen captures be saved
as .gif? If so, why is the default for RoboScreenCapture set to
save as Windows Bitmap?
thanks!

Answer 1

Graphics Tips for browser-based Help Guides.
============================================
For any web-based application, whether web sites or Help
projects, try to minimise file sizes for quick download speeds, and
optimising image sizes can make a significant differnce. for screen
shotes, I strongly recommend kind of graphics package to reduce the
number of colours. I use Paint Shop Pro, but there are many others
on the market. (Sorry, MS Paint doesn't do what you need.)
Which Image Format?
===================
BITMAP
These cause HUGE file sizes, and you should never need to use
them. I just took a simple 980x530 screenshot of some text in MS
Notepad, and this created a 1.5 Mb file, compared with 114 Kb for
JPG and 28Kb for a GIF. ('Nuff said?)
GIF
For screen shot images, diagrams or line drawings, use GIF
format. This works best where there are areas of solid colour and
sudden changes of colour where you have lines, boxes and text
superimposed upon it.
The GIF format is limited to 256 colours, so you will need to
reduce the number of colours in your favourite graphics package.
Reduce colours using the 'Nearest Colour' method; do not use 'Error
Diffusion', which makes a larger file size. The result is a clear
image and compact file size. Where possible, reduce the number of
colours as far as you can, consistent with retaining good
appearance. If you can reduce an image as far as 16 colour GIF,
this will give you the smallest file size.
DON'T use GIF for photographs because of the bands of colour
that show across the photo, which it tries to fit into a 256 colour
palette.
JPG
JPG is optimised for photographs, where there are gradual
changes in shade and colour.
DON'T use JPG for screen shots because you end up with a
larger file size and a 'gritty' appearance, as JPG tries to resolve
the suddent transition between background white and solid black for
text, for example. (See file sizes of example above).
PNG
NEVER use PNG format in RoboHelp because it makes RH unstable
and cause crashes. Trust me, I know: it has cost me many man-days
downtime over the years, caused by restarting from crashes and
tracking this bug down.
TIP for smaller screen shot file sizes
======================================
In Windows XP, switch off the default "smooth edges of screen
fonts" feature, as follows.
1. Desktop > right-click > select Properties.
2. Select the Appearance tab, and click on the Effects
button.
3. Clear the checkbox "Use the followng method to smooth
edges of screen fonts".
Depending on the screen shot, you can save up to 40% of a
finished GIF file size.
Hope this is useful!
Best wishes.