I just wanna know how to take a pictute while video recording is on in phantom 4? Thanks.

Not possible. Have to stop recording take picture restart recording

Yea, I have a DSLR camera that will do that, but unfortunately the Phantom won't.

Unless you need a high rez photo, I've found that screen grabs from the video will produce images good enough to display on my computer screen or tablet.  1920 x 1080 video nets a 2 megapixel still image and 3840x2860 provides an 8 megapixel still image.  I'm actuallyl building up a collection of images extracted from my video streams.

Record 4k video, u get a better still out of it. I always take 2.7 K video on my P3advanced, just for that reason.

Phantomski Posted at 2016-6-3 05:59
Record 4k video, u get a better still out of it. I always take 2.7 K video on my P3advanced, just fo ...

Stills from video are always going to be a poor substitute for real photos.
From 2.7K video you only get a 4MP still
From 4K = 8.8MP
And that's before you consider  the  shutter speed effect.