no, irfanview has a lot going for it - although you can't create images from scratch, it's ideal for the client who has a photograph and just needs to resize/resample/crop an image. It does stuff like sharpen/saturation etc but it's also able to have other filters like Optikverve which does a huge range of effects (it'll also open photoshop filters). It's small, free, really easy to use, creates slideshows, screensaver etc...
Even if you go for gimp or something, irfanview is still a hot download and it'll probably do 80-90% of what a client would need.