I have an image, which have some amount of semi-transparent pixels. I would like to blend them with white:
How do I do it?
I don't think you need to technically blend them with white; you want to change the opacity to 100% , which is what your second image looks like. Put the art (lavender and black) on a separate layer from your background (if yo want to maintain a transparent backround) and change the transparency slider to 100%
There’s a few ways to solve this, but no matter which approach you take, you’re going to have to re-work or trace the edge.
One simple, but slow way to do this, is to paint underneath with white. You can do this with a shape layer, or a bitmap layer. If the stroke is opaque and wide enough, this will likely be the easiest way to go.
Another option is to open the image, and make lots of copies of the layer.
This will give you the the result you’re after with one major flaw: The partially transparent edges will now be aliased (jagged). You’ll have to use a different technique for fixing the edges.
It's a bit hard to give you a straight answer on that.
But through the images you've posted you already answered it.
1 create a new layer bellow the art one
2 create a lasso selection along the black line of colored area
3 fill with white.
Then I would CTRL+E or Cmd+E both layers.