There is no such thing as .scj. However, there is .scm that is used by by StarCraft as a game map. .scm includes various types of terrain and resources and are created in different sizes, including 96x96, 128x128, 192x192, and 256x256. Actually there is a .scj file format but only two PC games use it as far as we know. They are, Jurassic Park Dinosaur Battles and Jurassic Park Scan Command.
You need to convert the picture to a .wad file and name it tempdecal.wad. It must be a size divisble by 16. (ex: 16x16, 96x96, etc) Put the file into C:\Program Files\Valve\Steam\SteamApps\<username>\Counter-Strike\cstrike\ Then right click it, enter properties, and make it "read only". Now you can spray the picture inside the game.
You can, if this photo is saved in GIF for example (or any other format that does not use any variable compression). In this case simply reduce the output image size until you get the 200kb. If you save it into JPEG you have to reduce the size so that with average JPEG it is a little bit lower than 200kb, than slowly increase the quality of the JPEG until you reach 200kb. It is hard and there is no quarantee that you will land exactly on 200kb. It may be few kB more or less. Try using AZImage - see reference. It is a simple to use tool that provides also the advanced features you need. To have a quick preview search on youtube.com after "resize azimage".
There is no way to give a real answer for that. Pixels do not have a consistent size, so they can't be universally converted. Pixels change size depending on the density of the thing displaying them (72 dots per inch is typical for screens and 300 dpi is typically selected for something that will be printed as form of Quality Photo). For screens size differs based on "Pitch" of the screen(distance between two consecutive pixels) thus even small screens with low pitch value can display high resolutions!However, to simply measure the width and height of your monitor at high accuracy just use the "Jruler" applicationDownload JRuler from here:JRULER