Help please- little grey patches on CAS items

They are missing pixels, the edges of a texture is always prone to blur and degrades a little when imported. I make all mine in .png and only convert them to .dds when I am sure the texture is finished, but I still get this problem sometimes.
I think its worse when making clothes as the edges are much more important, they are on show constantly whereas furniture is only really seen in passing. I sometimes take the offender back into Adobe and try and retouch the edges in .png then after testing convert to .dss. Sometimes it works other times I need to make a new texture from scratch.