I have no idea what LINE Camera or PicsArt is / are, so going by the title. "How do I make those soft, fluffy things transparent?"
First the source of the images, The ones posted are jpegs, jpeg does not support transparency. Is there any possibility that you can download a png version that might be partially transparent?
Using what is posted.
Normally, Adding an alpha channel Layer -> Transparency -> Add Alpha Channel then remove white with Colours -> Color-to-Alpha and adjust the opacity slider to suit works. However too much white makes up the pink color and that method is not so good, too faded.
Try using a Layer mask Layer -> Mask -> Add Layer mask Choose a white mask and paint a black-to-white radial shape gradient to suit. When satisfactory, Layer -> Mask -> Apply Layer mask Remember to export your frame as a png to preserve the transparency.
example: https://i.imgur.com/bUQcm2V.mp4
A radial gradient might be too regular for some of the images, Again using a white layer mask. Use an elliptical selection, give it a big feather Select -> Feather and fill with black. Finish with Select ->None and Layer -> Apply Layer Mask. Export as a .png
example: https://i.imgur.com/2Cwbsgv.mp4
First the source of the images, The ones posted are jpegs, jpeg does not support transparency. Is there any possibility that you can download a png version that might be partially transparent?
Using what is posted.
Normally, Adding an alpha channel Layer -> Transparency -> Add Alpha Channel then remove white with Colours -> Color-to-Alpha and adjust the opacity slider to suit works. However too much white makes up the pink color and that method is not so good, too faded.
Try using a Layer mask Layer -> Mask -> Add Layer mask Choose a white mask and paint a black-to-white radial shape gradient to suit. When satisfactory, Layer -> Mask -> Apply Layer mask Remember to export your frame as a png to preserve the transparency.
example: https://i.imgur.com/bUQcm2V.mp4
A radial gradient might be too regular for some of the images, Again using a white layer mask. Use an elliptical selection, give it a big feather Select -> Feather and fill with black. Finish with Select ->None and Layer -> Apply Layer Mask. Export as a .png
example: https://i.imgur.com/2Cwbsgv.mp4