It's impossible to give guarantees via an online forum; however, it appears to be a grade one strain.
What interests me about your comment is that your left oblique is significantly more hypertrophied than the right. Unless I misread your earlier posts, this is also where the strain is (although it is premature to rule out hernia - although it appears less likely).
I don't believe this is a coincidence. In other words, the fact that your left oblique is visually larger than your right tells me that you are most likely engaging that side more.
Let's take your tricep push downs, for example. Even with excellent form - indeed, in an effort to maintain excellent form (as defined in this case as a "motionless" torso) - there is still a certain amount of anti-extension within the movement. There could also be a degree of anti-rotation depending on the angle of the cable in relation to your torso. This involves the internal/external obliques (as well as the rectus abdominis). Is it possible that you are performing this or other lifts in such a way to engage the left side of the abdominal musculature more? I would not rule that out at this point.
And why is there no discomfort when performing leg raises...? It could be that your psoas major/minor, iliacus, rectus femoris, and possibly even the sartorius (yes, one of its functions is hip flexion) were acting in concert in a synergistically dominant manner. The body simply hates being in pain; it will do many strange things to avoid it.
The take home to all this:
1) it is most likely a grade 1 strain
2) do not rule out the possibility of a hernia
3) re-examine how you move, stand, sit, lift, etc.