OK just got back from vacation. First the reason is the fat table inside the game does not extract the fat table out of the bigfile therefore that is why the difference in size of 1 mb. second if you replaced files inside the @extracted folder then it depends on your next step. Some files just can't be replaced it depends on the file itself in some instances it is better to replace with a 1kb dummy but certain games need dummy files of certain lengths.
If you dummy anything with a 0kb dummy then relinking you need to do. with my tool just find the lba.new file created in the @extracted folder after you dummy items and pressed the rebuild button you'll find this lba.new file the relinking is done here cut and paste the start lba and size lba of a file you wish to keep and paste it over one you dummied if you used a 0kb dummy then you will see the file like 123478CA|00000000|textures_hdl_bat.tex this is an example. then after you do all that you then press the rebuild lba button on tool.
try to be more specific when asking for help did you get the size down to burn to cd-r or did you burn to a dvd are you using swap magic cd since this was a pal game you must have the pal version of swap magic to boot. Also, most times when you get a blue border the problem lies somewhere in the game itself if you burned to a cdr did you find all the dvd checks in game and remove them and patch all the iop files as well.
As to viewing the .tex files of the game not all .tex files are graphic texture files some are plain encoded text files of the game and most of those files are compressed and would require a decompressor to uncompress them and a tool convertor to reconvert them back into their viewable image. You could try some .tex converters for some of the pal soccer games they may have the same format.