It was probably spurred on by the increasing ease of travel with the development of the Railways, by improved living standards and wages (for some), greater urbanisation, the rise of the theatre (and later film) star and, more particularly, advances in photography and printing.
I addition to the path's trod by many, into Victorian erotica which was a great field of study for the rich, but not for the more honest (or should that be Horny), the entrepreneurial photographer had, by the turn of the century, 30 or 40 years of peddling his trade from village to village and town to town, where the locals from Apple sellers to Zoo keepers, from youngest child to those in their dotage, the housewife and the harlot, and farmers and farmhands, schoolmasters, pupils, constables, scallywags, and vicars and drunkards queued to spend a few pennies and have their picture taken. Changes were offering new opportunities, cards with pretty faces, pets and places, humourously immoral or upliftingly moral could be sold to anyone. All that was needed was constantly changing variety that with mass production to keep prices low could attract an ever increasing mobile population to but and to send postcards. Look at the messages on the back of a postcard, it is a precursor to the e-mail or an entry on facebook. How many say "...Arrived safely..", "..be arriving...", "...sorry to hear you're unwell.." They were the means to keep in touch with family in a pre-phone society and at a time when the Post Office was a service and delivered 3 times a day at least.
Card one is not used so their is no date of postage, I'd place a guess as the 1900-1910, and whilst it has nothing to say what it is, the print on the reverse suggest it is French. The subject is perhaps just an little too cute and suggestive for today's society of ignorant suspicion and overwhelming willingness to blame and accuse.
I haven't been able to find much about the subject in this card. She is Olive Miller (better-known under the stage name of Olive Morrell) in London in January 1908. longShe was an opera and popular song singer and actress and married an Australian MP, but that didn't last long
This a birthday Card Given but not sent a Eunice. It appears to have been printed in Italy for the British market. Around the turn ??
There are more pretty faces, as well as the Pets and Places, and other things that didn't help the title, to come as and when it happens. Feels free to comment, criticize or add any information on the cards or the subjects, it will all be appreciated