If your images are looking a bit washed out, which I assume is overexposure, have you checked your camera setting. With digital photography it is often better to underexpose, then correct in software later.
Most cameras have an option to reset to default setting in the menu.
I am not sure what you mean by 'one touch'.
Do you mean a photo editor that has limited options i.e. brighten, darken, reduce in size or enlarge.
Or something with several option that you can choose from i.e. Convert to greyscale, increase/decrease colour depth, colour correction, auto-adjust colour, sharpen.
I am not sure why your current package is resizing them, it may be a preset option that needs resetting.
But while on the subject of resizing, it is not as simple as it sounds. There are quite complicated algorithms that achieve it, but they can be caught out if the image is 'complicated' i.e. lots of contrast, changes in hue, saturation and brightness. And that is before you look at printing option where there can be a clash between RGB and CMYB.
Computer monitors can also be set up differently, though this is generally less of a problem these days. Took me days to realise that one PC I used was set to 16 colours (4 bit). My current monitor is set to 32 bit, which is 4,294,967,296, or a silly amount of colours.
For quick image manipulation, I use Irfanview. It is pretty basic and only has one 'undo', but is a small package that does most things.
It is also available as a Portable App, which means that it does not scatter files all over the computer as it is not really installed as such, it just sits in its own folder. This means that a shortcut to start it needs to be created and file associations made need to be changed so that images open up in it by default.
But it does have some simple 'one touch' presets to enhance the image and an easy resizing option.