You may be tempted to make a WAP phone message picture from a photo...
Even with thousands of colours, it isn't always easy to reduce a photo to tiny size. The thumbnails on my iPod Nano are not always recognisable. When you only have black and white to play with for a tiny image, you'd be better to do a drawing.
You don't have to play with digital pictures for long to realise that reducing them makes them sharper. Down to a certain point.
When you get to the size of a message picture for older phones - or any tiny image in black and white - you enter the nano-world of graphics. Different rules apply!

Here's an original digital camera image (background removed) converted to black and white for a tiny two-colour graphic

Here it is reduced to 25% [27 x 30 pixels]

This is the icon-sized image re-enlarged to show you what's now missing
The picture has started to fall apart at a this very small size. You just haven't got enough pixels to make anything more than a crude mosaic. Without colour, the amount of information you can show is even more drastically reduced.
A stem might make that doughnut look more like a flower - but no stem was visible in the original.
The black square doesn't help. A tiny mobile phone message picture or logo graphic needs a good outline to stand out. And who wants a gloomy sunflower?
How about turning the background white...?
You do at least have one advantage when working in black and white. You don't have to worry about transparency. Boxes around images disappear when they're white-on-white.
Shapes that are dark at the outer edge work best. Silhouettes are effective, especially for icons. But here, the sunflower centre has to stay black - and there's no room for outlines.

Here's our original sunflower again. This time the black and white version is 'Edge Detected' in Photoshop.

Here's the resulting icon sized graphic, re-enlarged
Bear in mind that on an older phone or Palm screen, the message picture won't even look that clear. 'White' will most likely be yellowish green and 'black' will be grey.
If you're still determined to make a WAP phone message picture from a photo, crop to the smallest possible part of it. Remove the background, then reduce the image size as much as you can before you convert to black-and-white. Photoshop Elements Save for Web will do the
colour reduction for you.
You'll probably still have to tidy the image up. In fact you'll probably end up having to redraw it anyway. It's really much easier to draw the whole thing from the start! At the tiny size of mobile phone message pictures, it really isn't difficult.
Can you make a WAP phone message picture from a photo?