Image Converter

I Need To Convert From Image Formats ( Bmp,gif,pcx,and Tga ) To Ppm And Viceversa On Command Prompt ( In Dos)
Can Anybody Tell Me Freeware Exe Available On The Net.
Has Anybody Used Dos Execuatble Of Pbmplus Package .in Fact That Will Also Do.
I Know Google Is The Answer.but Someone Else’s Experience Will Help Me In Getting The Right Thing Fast . Moreover The Net Speed Here Leaves Very Little Scope To Search A Lot.
Thanks In Advance For The Guidance.

Try this: http://www.imagemagick.org/