In case anyone else was curious about using a lookup table: there are there are fewer than 256 recognized countries or territories [1], so 8 bits should be enough for a key.
This would be superior to the 11-bit encoding presented here because it handles complexities such as coats of arms. It would also handle bizarre situations such as two countries having almost identical flags [2].
you could also exploit the fact that some flags may appear more frequently than others and use huffman encoding or something to encode the commonly used flags in a shorter sequence than rarely-mentioned countries, and save some bits on average
Cool idea. Interesting that Indonesia, Poland and Monaco with very similar two-stripe designs have different compression rates (11, 14 and 17 respectively). Probably the aspect ratio that also gets encoded.
This would be superior to the 11-bit encoding presented here because it handles complexities such as coats of arms. It would also handle bizarre situations such as two countries having almost identical flags [2].
[1] https://en.wikipedia.org/wiki/List_of_countries_and_territor...
[2] https://www.worldatlas.com/articles/country-flags-that-resem...
also then it's no different from a svg sprite