There are arguments supporting both schools of thought but consider this... That fact that you have to "try to make it comfortable for the mobile users" should throw a red flag. Anytime you have to force the content or the UI to work, you can pretty much bet the users are going to suffer for it. Start to move away from looking at the process of building web based projects as responsive / adaptive, vs. static. View the process more as the modern way to build such projects going forward. Planning out your content flow is key. Understanding the hierarchy of the site and it's content structure will allow you to design better flow patterns for the various devices out there.

I recently had this discussion with my Wife who was working on a redesign project. I advised her to first analyse the content and start with mobile. That way she didn't have to try and force content to fit into the smaller form factor thus allowing her to design a better experience for the user. She was a bit reluctant at first because she, like yourself, likes to start with desktop and then try and solve the issues that arise with tablet and mobile. She found this approach easier since it allowed her to "expand" the site and the content as she moved from mobile, to tablet, to desktop.

In addition to this, whenever I design and build a site, because of the various breakpoints, I use fewer rules and media queries when I start with mobile. All the major UI styling remains consistent through out devices only changing when the content needs to be presented differently.

I hope this shines some light on the subject for you and good luck with your projects.

I do it the same way, Developing for desktops and then going down for mobiles.

In my opinion, going mobile first can make your development process desktop second

Don't get me wrong here, I do believe that mobile first approach is great and solves a lot of problems and the response by @xirclebox is also pretty accurate here but I also believe that desktop web has a lot of potential and by focusing more on mobiles, when we "expand" our design, we tend to ignore that potential.

This said, I think would still say that mobile first is pretty great if you have the right content and design for it. But if the content demands it, go desktop first!

i have a using a boostrap for responsive process but image prbm for all devices is still not find out,can u pls tell me the image responsive concept