Cloud of smoke when starting

Hello. I'm a first timer so pardon my descriptions.

When I start my engine from long periods of rest (overnight mostly), it fills up the place with visible smoke and then ceases to do so after about a minute, two max of idling. This is rather troubling as it only did this twice or thrice a week but ever since I had a mechanic change my engine oil and leaky top engine seal, it's become an everyday issue. It can get rather embarrassing.