To me, that sounds like the compression is at least reasonable.
At least reasonable enough that it would at worse run rough, as opposed to not running, the pictures should help though.
Lets give the spark a full test (using the above mentioned methods) now theres 2 ways i tend to do this, you can choose either at this point.
1)Remove the rubber boot from the end of the spark plug lead (should be fairly easy on your mower) but leave the contact screw in, then, using a clamp, or vice-grips (locking Pliers) secure the lead so that the screw is 3mm from a clean, unpainted metal part of the mower (make sure the screw is not making contact with the mower, or the pliers/clamp)
or
2)Get a spark plug that you know for sure works, and using wire cutters, or a handheld rotary tool, remove the bent piece of metal that the spar travels to, crating a 3mm or so gap between the centre rod, and the outer rim, then clamp this plug to the mower, making sure the centre rod is not contacting the mower, but the outer metal casing IS, and connect the lead.
Take the mower to somewhere with low ambient light (inside a closed or semi closed shed is good, but any were dull will do) and give the cord a few strong, fast pulls, with the throttle set at run (make sure the fuel is off, and there is no spark plug in the spark plug hole, also, it is best to make sure the test spark will be away from the spark plug hole, to avoid lighting any expelled fuel)
What is the spark like? (colour? [could be yellow, or more a blue/white] strength [wispy and thin, or strong and fat] and any accompanying noises)
