Even the position paper from the PNG development team was quick to point out that it isn't supposed to replace JPEG compression. Unless you were planning to offset print that image, a 60% lossy JPEG is usually indistinguishable from the original, even with superimposed text, even when zoomed 200%. Shame the browsers haven't adopted the JPEG2000 standard; it compresses smaller, its replacement for the standard progressive format would allow you to use the same file for the image AND its thumbnail (the thumbnail load gets just enough data for the thumb) at whatever reduction you like, ANDDD... artifacting is virtually unheard of due to its zig-zag diagonal image sampling.