I see from your screen capture English is not your normal language.
Though English is my native tong I'm not good with it. I do not understand what you are doing Your screen capture seems to show Photoshop Captured with a frame animation where each layer is a smart smart object layers and in frame 20 all layers in the part of the layer palette that I can see are visible and the frame composition does not look like what you would want frame 20 to be. Photoshop does not have the ability to save out animated png files and all browsers do not support animated png files. I have and APNG Chrome extension installed so they animate in Chrome on my Windows 10 machine. Opening an animated png file in Photoshop seems to just open frame one into Photoshop as a single layer document. Here is a link to some animated png files.http://www.mouseprints.net/APNG/
I do not know what you mean where you wrote::
I want to convert this animation as a PNG images compilation.
I made an animation of a man walking.
When I convert this animation (which is a .psd file) as a .mp4 or .gif file, everything is fine : the man walks exactly like in photoshop.
But when I convert this animation as a PNG images compilation, the images do not match which my initial animation : the man is dismantled, you can see the result on my screenshot.
When you have a problem in Photoshop it is best to search this forum before asking questions to see if there is an solution posted for your problem and if not post the problem you are having anf the Photoshop steps to reproduce your problem.
You wrote "I convert this animation as a PNG images compilation" by that I now believe you may mean you tried to use menu File>Export>Render Video and in the render video dialog tried to save out a sequence of PNG Image files. Searching this forum I find results like it a bug in CC 2018
All version of Photoshop contains bugs. It is best when installing new versions of Photoshop to keep working versions of Photoshop the work well for you installed using the advance install option to keep old version installed. Otherwise Adobe installer will remove old versions of Photoshop. You can remove later versions that you doe not want. These days I have three versions of Photoshop installed. CS6, CC 2014 and CC 2018. I normally use CC 2014 it the best version for me. I play CC 2018 it has new and old bugs and new features.
I look at your animated Gif. For you did not post your layer document with smart object layers. All the frames in the animated gif have a white fringe around your figure. I removed that white fringe save save out a PNG sequence with a black background and one with a transparent background using CC 2014.
CC2018 has a bug Adobe may fix it.
Thank you !
I was not trying to use render video, I was only using the bottom left button on the animation panel that I have previousvly shown.
So I tried to use render video > PNG, and it worked !
I have now my PNG images sequence, not dismantled at all.
Also, can you send me the PNG sequence without the white fringe please ?
I did not see it before. Would be very nice.
I can not send the png sequence for I deleted the files, Also I created it using you Animated gif so the colors are only Gif quality. I just created an action to select the layer's transparence contract the selection 2px inverted the selection and cleared the white fringe. it then selected the next layer up I played the action 135 times. I do have the trimmed animated gif, You can open that in Photoshop as create the png sequence. I believe the problem was fixed yesterday. I have not installed the CC 2018 update yet.,