OK - XP can do it. To save the JPG requires a "Save as".
It doesnt appear to allow a choice of the level of compression which will be why you had large pixels.
Irfanview is vastly than paint. I like its ability to do JPG lossless transformations to convert portait to landscape and vice-versa but keeping all data in the image including the exif data and it doesnt change the data written. Excellent product!
BT Infinity 2 - IP profile 77 / 20 - super fast!
Previously BE Unlimited - 21,000 Download 1,200 Upload but then moved house - 6,500 Down, 1Mb/s up - gutted!
Ex <n>ildram , been to SKY MAX - 15,225 Download