By RAW, no.
Keep in mind, not every creature with the Fire Subtype is in flames.
However, it makes sense that a DM might rule that any creature that is in flames would put off light like a
Torch, or however else they might want to rule.
I'd guess that if fire was on the surface of the creature's body, it doesn't matter the creature size, it'd still put off the same amount of light and I'd go with the torch.
If the creature's entire body was composed of flames, I could see a further light radius.
But this is all in DM call territory, and not RAW.