I have a thorough understanding of high resolution vs low resolution photos, print vs web resolution etc, that shouldnt be the problem here, at least not entirely.
Does anyone know why some photos get a grainy "halo" around the edges of objects within a photograph when you export them for web? And/or what that pattern/issue is called? See my example below. Along the edge of the passport seal, its extra grainy and pixelated. I highlighted a portion of it in yellow, but if you look closely, it's happening around the entire seal. It also appears around the "United States". This is the most recent example I have but its been a random problem for me forever, usually around edges and text in photographs. I dont know what its called to google it myself either.