Functioning problem with wc3 image extractor 2

[Gatreh]

Hello, I'm REALLY new to this forum as I just started making maps and already encountered problems :s
For anyone that hels me I'm sorry for taking your time, now onto the problem.
In the tutorial about making a map background found here.
It does way I should open the image extractor but it dosen't say what .mpq file I should open. After reading a bit on this forum I came to the conclusion that it should be the war3.mpq (or war3x.mpq) Although when I open these and try to upload my picture to be able to make it into a .blp file.

If by any chance I would like to do this myself, meaning I don't want anyone to do it for me.. Some better instructions on what .mpq file and how to use the tool would suffice more than enough thanks on beforehand.

 

[Gatreh]

Bump, I'll start working on some other things in the meantime ^^
Gonna check back in about 3-5 hours
Edit: Still nothing D: noone knows how to fix this?

 

[Gatreh]

Bump, Really need help with this >.<