Provide image taken from a little further distance away. This is like the game where a close-up picture is provided and everyone guesses what the picture is of.

Tiny photos. Don't reduce the quality.

Could they be finger jointed studs?

I've never seen that done. Putting a cut like that in a warped piece of framing lumber would allow "straightening" it, but it also seriously reduces the strength. A competent contractor would not use a piece of severely warped lumber, or would use it elsewhere in smaller pieces. You may want to see what the building department has to say about that. In my area, I'm not sure that would pass inspection if it was spotted. I also see in the second photo that you have untreated lumber in direct contact with concrete and I can't see any barrier between the two. If this is an exterior wall, that's a no-no. If it's an interior wall, it may be ok in your location, but I'd ask the building department about this, too.

Typical stud straightening.

Warped stud is cut, new straight piece installed beside.

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The framing carpenter would typically do that just prior to the drywallers getting to work.

After we switched to 2x6, I can't even recall the need to do such. 2x4x10s were getting impossible to work with!

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you have untreated lumber in direct contact with concrete and I can't see any barrier between the two.

It shows as green on my monitor.

You have no idea how bad the quality of wood that shows up on job sites is. A quality contractor will also 'shave' all the bowed studs so that your walls are not wavy once the drywall is applied. It makes you want to contractor for a steel stud house. Those are straight.

It depends upon whether or not the wall is structural. You can cut to straighten the studs in a non-load bearing wall all you please; it only has to hold drywall and electrical boxes and better it be held plumb and flat.

I agree with 3onthetree but I am not fond of 2 x4 framing ever where are you that this is even done anymore . I live in canada 2x4 framing is not even done here at all.

Same thing was done on my house, job supervisor said it was too straighten warped studs.

This looks like above average care was taken, you are lucky.

"I am not fond of 2 x4 framing ever where are you that this is even done anymore"

There's nothing wrong with 2" x 4" framing for most residential construction provided the required R-value insulation can be installed in the stud cavities or (preferably) it meets code requirements when combined with continuous exterior insulation.