There are plenty of photos of people on bicycles in the 1890s to be found, but of course they're in black and white. So I spent a delightful couple of afternoons at the British Library earlier this year, looking at The Tailor & Cutter journals from 1896 and 1897. Some of these included colour "fashion plates" - illustrations which tailors could use to advertise their services, and cycling having become very popular in the 1890s, there were a few showing people with bicycles. I also found fascinating references to cycling wear in other written materials.
"The fashionable Cycling Costune just now for gentlemen is evidently the Lounge and knickers, the vest being optional. The old style of tight fitting breeches is quite a thing of the past..."
-The Tailor & Cutter, January 1897
"The beautifully coloured litho Plate we are giving with this issue illustrates one of the most popular types of jackets worn at this season of the year, viz., the Norfolk jacket. There is scarecely a sport in which it is not used, whilst for golfing, cycling, pedestrian and fishing exercises it is considred by many to be the ideal garment. Our illustration shows it in its simplest form, viz., with one pleat up each forepart and down each side of the back. Large patch pockets are added to each side, and the general get up of the garment is loose and easy fitting. ... It usually forms part of a knicker suit, the cap being of the same maerial, and the hose made of similar colour to the suit."
-- The Tailor & Cutter, 1896
"He had on his new brown cycling suit - a handsome Norfolk jacket thing for 30s - and his legs .... were more than consoled by thick chequered stockings thin in the foot, thick in the leg."
- H.G. Wells, The Wheels of Chance, 1896