As Roger pointed out that yes there are some violations we can see in the photo, to what extent of course will take a good electrician to go through as a photo can only tell so much, but the fact that the sub-panel is tapped on to what looks like the main service disconnects line side can be very dangerous if the sub-panel is any distance somewhere else in the home, this is because the line side of the main is not considered protected by any over current protection and many times if ever shorted could burn through because there are no fuses or breakers that would trip, this could be a serious hazard if so.
But I noticed that the cable feeding the line side of this breaker is a SER meaning it has 4 wires two hots a neutral and a separate bare ground, it would be un common that an electrician would use such a cable unless there is a disconnect that maybe is also have fuse/breaker protection located between the meter and this panel in the photo, this would make this panel also a sub-panel, while this does give the smaller conductors tapped to the main some bit of protection in a case of a fault much would depend upon the sizes of these fuses or breaker in this other disconnect, it still doesn't lesson the fact that they could be still overloaded as they are not protected at there rated value so it is still a very serious problem.
But as Roger stated, you need to get a good qualified electrician to look at everything as there could be other problems, and when I see things like this I tend to dig deeper as I want to know that my customer will be safe when I'm done, and I'm sure you would want your family safe also.
Also I see a cable that looks like tray cable that is almost as large as the SER cable feeding this panel, but it only has a white and black conductor and what looks like a bare ground covered in a paper wrap, while this may not be a problem if it feeds a load that is 240 volts only and doesn't need a neutral if the load it feeds doesn't have 120 volt loads it could also be a problem, , also there is a breaker that has two wires to it with one being white, I'm not sure if cutler hammer CH series breakers allows double taps as some breakers do, but what concerns me is that fact that a single pole breaker should never have a white wire to it, again this should be looked at by the electrician you get.
And being able to sleep well knowing that you have a safe electrical system is worth the price you pay for a good qualified electrician, just like I will spend the money for a good mechanic for my car as I want it done right, and want to know that if I have to stop to avoid an accident that my brakes will work like they are supposed to.