Can i use SMD Led with normal size components, let's say i want to make some electronic project with running led can i use SMD LEDs instead of 3mm or 5mm led..?
Can i connect normal size resistor to smd as in the photo?

 

Yes you can use any size that is adequately rated for the application.

 

That resistor has nice leads which can easily be attached to lots of other things.

SMD (Surface Mounted Device) parts are intended to be soldered down to a printed circuit board, and since the attachment area is quite small it is quite hard to use them with anything but a printed circuit board.

So just what are you trying to do with these LEDs? The more you tell the better the suggestions get.

 

make some electronic project with running led can i use SMD LEDs instead of 3mm or 5mm led..?

You can do that, but your mounting options for SMT LEDs will be more limited. With through hole devices, you can mount on a project box and run wires to the LEDs. You can't do that with SMT devices.

 

Light pipes are mentioned in a nearby thread and they are certainly the most common way of putting surface mount LEDs to use as panel indicators. Two real benefits are there, ruggedness of the light pipe and isolation from static discharges at the panel. Another benefit is that it allows more freedom in locating the LEDs.