No that won't work, that's a composite cable. When you see the three RCA/phono/AV cables like that, if one of them is yellow, it's composite video. Even if you feed it into a scart block like your example above it's still composite.|
An RGB cable looks like this:
Notice it goes straight into a scart lead.
To complicate matters, there are probably some cables out there that even though they go straight from the console to a scart lead, it's still just composite video, so don't think scart = RGB. You can tell the difference by looking at the pins on the scart block; an RGB cable will have all the pins there whereas a composite scart lead will have some missing.
I've probably gone over-technical but all you need to do is make sure the one you buy is advertised as RGB.
21 consoles, 5 handhelds, 2 PCs, 1 Mac and about 700 games from the past 30 years. Every major manufacturer and developer represented. Still a fanboy for disagreeing with you.