Firstly I know StackExchange have a similar question. But I'm unable to comment on that question due to low reputation.
Coming to my issue Chrome browser showing images in small sizes since last week. I have tried clearing cache, site settings and also tried clearing all my chrome data from settings-apps menu. I'm using updated Chrome browser (v62.0.3202.84) and my phone model is Moto X Pure (Nougat 7.0 updated)