Actually ....
I am about 99.53% sure that these prebuilt images from Alex are:
- a) vanilla, and so uclibc based, and so opencv will not work in these images
- b) both require you to update the stock firmware in order to work correctly. I know you can do that via serial link because that's how I did it.
Let me go back to the original posters question.
As far as I know (and I have personally done this, and I know it works)
1. In order to make opencv work, yes indeed you do need to rebuild, from scratch, using the yocto build environment, an eglibc based Linux image. This will take several hours but works pretty much as described by Sergey.
2. Strictly speaking, you do not need to follow the complete instructions in Sergey's blog (although it is useful to do that). Following Sergey's instructions to the letter also gives you a galileo image which contains a full development toolchain. This is why you increase the size of the SD image to 3GB
3. I don't understand OP's question (2). Perhaps you can elaborate?
4. If you mean "compile opencv from source on the galileo", I tried that too. Don't bother. While building it will work, if you do it correctly, it will
- a) take ages, and
- b) not work anyway. OpenCV just doesn't work on the uclibc based images.
5. Finally, if you *do* rebuild a Linux image based on eglibc, you will need to rebuild the cross compiler toolchain in order to make Arduino work and hook it into your Arduino IDE. This works too, and someone just posted yesterday how to do this for Windows which I haven't tried yet, but I will soon.
I have a prebuilt image, eglibc based, 3GB in size (although it compresses down a lot more), including toolchain, with working opencv.
If you don't mind taking an image from a complete stranger, I'll upload it for you to someplace later this evening. It is more or less the full "sergey" build, with one addition. I have enabled swap functionality because I am trying to build something which won't build without swap. (dunno yet if it will build ~with~ swap, but that's something to try for later this evening)
Unpack to SD card
Boot
Enjoy opencv goodness
Regards
Liam