I have recently noticed a problem with the ride quality on my bike.

It just doesn't seem smooth anymore.

All the bearings seem ok and nothing seems to have come loose.

I just don't know what it could be.

Maybe someone could suggest what the problem is from the pic?

Check you tire inflation pressure! If that doesn't work, I think the Flintstones can recommend a good bike mechanic.

Neal

I think, if you watch as the front wheel goes around, you'll notice a little rubbing on the inside of the fork.

The problem is your bottle carrier and your bottle. Move the carrier to the Downtube and find a bottle that's more rectangular so it doesn't conflict with your rims. That should do it.
If that fails, try changing that round chain wheel to a square ring.

Your chainline looks misaligned

Whatever the problem turns out to be, when you get it fixed, maybe don't ride it on the steps anymore.

Or ride it only on the steps.

what the heck is that thing.

Seat is too far forward and will make ride a bit twitchy, put it back and all your handling problems will go away

looks like toe strike could be an issue, have you noticed tire marks on the front of your shoes?

also on second thoughts look at the tread on the tyres- theres your problem

You need to ride on an inverted catenary road.

What you need is a nice Brooks saddle and perhaps a carbon fiber fork.