They are a lot fatter than 25s! The bike is an expedition type tourer with big clearances, the tyres were Vredestein Spyders 26x1.9, i.e. MTB tyres with a smooth centre and knobby shoulders. They were perfect for that sort of riding and even rougher stuff such as rocky stream beds where there is a risk of bashing the wheel rim on thinner tyres. The downside is that they are heavier and slower on the road than proper slicks, also, on the cornering when the bike leans a lot and puts weight on the knobbly bits, it feels rather skittish. They are best used off-road IMO.
Do you have anywhere in mind? The path shown is a route over the Eastern end of the Pyrennees from France to Spain, much nicer than the road if you have the time.