SD and HD don't refer to analog vs. digital, they refer to standard definition (480i) vs. high-definition (720p, 1080i, 1080p). Are you talking about these isolated examples?
It was not quite that. I meant that these articles with images tagged as "SD version" are captured from a analog broadcast.
The Brazilian digital terrestrial television system supports both SD and HD, but the country's big five networks (Globo, Record, SBT, RedeTV! and Band) broadcasts only in HD. This "SD version" refers to the analog broadcast. I think that these logos should be removed.