ORIGINAL: SeaMonkey
I prefer the Nato symbols, but I use the pictures simply because of the immediate feedback they give as to deployment so I don't have to interrupt my screen fixation by looking left to the info area.
The picture symbols don't give any information about deployment - to see deployment you have to press F5 and it then gets shown in the top right corner of the icon (the 'info box').
Where the picture symbols do give more information is that they differentiate between mortars and field or infantry guns, and between heavy and light flak units. Like the NATO symbols they differentiate between motorised, mechanised, glider, para and plain foot infantry but apart from that, they don't give any information about mobility (foot vs motorised/tracked). The picture symbols also don't differentiate between infantry and unarmoured cavalry/recce units although in game terms there's really not much difference between them anyway.
Regards
33