-(으)ㄹ 수 있다
-(eu)l su itda
Not ability — an open door
The picture A door stands ahead of you. If it's open, you can walk through. What opened it might be your skill, a rule, or just today's schedule.
Where the picture shows up in -(으)ㄹ 수 있다
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your skill opens the door
저는 운전할 수 있어요.
jeo-neun un-jeon-hal su i-sseo-yo
I can drive.
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asking whether the rule opens it
여기서 사진 찍을 수 있어요?
yeo-gi-seo sa-jin jji-geul su i-sseo-yo
Can I take photos here?
The same form does duty for asking permission.
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today's circumstances open it
오늘은 일찍 갈 수 있어요.
o-neu-reun il-jjik gal su i-sseo-yo
I can leave early today.
Nothing to do with skill — the door is open only today.
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you open the door for someone
제가 도와드릴 수 있어요.
je-ga do-wa-deu-ril su i-sseo-yo
I can give you a hand.
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the door of possibility is ajar
비가 올 수도 있어요.
bi-ga ol su-do i-sseo-yo
It might rain.
With 수도 it leans away from ability and toward likelihood.