Getting away from the debate about pictures in books for a minute. Do you do reading practice with you DS when you're out and about OP? Because the first words DS 'read' were Tesco and Waitrose, our two nearest supermarkets! I imagine he guessed them from the colours having been to the shops but we used that to sound out the words. He was three. Then we left it until he started school in case we confused him. After that we got him to sound out street signs, we play phonetic I-Spy - saying the sound of the word rather than the name of the word. And we'd do things like, if we saw a cat, we'd ask DS how he'd spell cat - getting him to blend. Then we'd write down cat, kat, Kate, care, when we got home and would get him to decide which was right.
And we read to him. A lot. He had, wait for it, four stories at bed time before he could read properly - Mr Men, thank goodness, were/are a favourite and they are quick and fun to read. We'd use our finger to go along the word and, now and then, we'd ask DS what a word said. No picture clues in Mr Men, though there are pictures on each page so he had to learn the word. He now reads them to us, putting on silly voices etc.
He's now six (year one) and, this evening, was reading Horrid Henry to DH. He's not unusual in his class.
He also reads the newspaper over our shoulder - which is a pain cos then you get into a conversation about all the bad stuff in the world. BTW a very dear friend of ours told me that she learned to read using the newspaper. No pictures to help and there are some fun things in most papers. She was struggling and her dad would give her a word to find on one page of the paper. So one day she'd have to underline the word 'and', next day it could be 'can' - she got a tick for each one she got right and penny if she got ten...mind you she will be 100 years old this year and a penny was a lot then - so after a month of her getting better and better the rates changed
. Before she knew it she was reading.