May 20, 2021
Hi, I have an Imedia s2870 and the PSU seems really crap.
The PSU is a Chicony D220A001L 220W Power Supply Unit - CPB09-D220A
Could anyone suggest an alternative that would fit in to this PC? The problem is it is quite a tight fit.
I need a new PSU that has better wattage as I intend on installing a new low profile graphics card and replacing the CPU.

Here is the inside of the PC. View:

Thank you in advance.
You're gonna have to just get the dimentions of the current PSU and go shopping (online or in store). Just make sure the PSU screw holes don't force you to install the PSU with the fan against the top of the case.
Also, keep in mind CPU cooling and cooler clearance inside the case if you're getting a beefier CPU. Some of these OEM motherboards can't even handle the higher performance CPU models because of substandard power delivery.

All in all, if it were me, I would take the money I was thinking of putting into this project and go shopping for a budget pre-built instead. You may have to add a little more $$$ but you'll get a MUCH better system all around.
best solution,
ditch that thing entirely and if necessary, start putting away some money for a decent build.

Could anyone suggest an alternative that would fit in to this PC?
a large portion of the pre-built systems, and especially older ones, use proprietary components that cannot be replaced by regular 3rd party versions.
you would need to measure the available space and the spacing of the screws and then compare them to any replacement to ensure compatibility.