I opened the image in iColorama. I used Effect/Pixels. I tried several presets, and I used the largest size setting.

Using Brush/Paint, I selected the off-white background color and painted away some of the image, to make more of a face shape. I saved this image to my camera roll. Then I painted over the entire image with a large brush with the off-white color, to make a solid color image. Then I used Effect/Blend to blend the previously saved image onto the solid off-white image. I used my fingers to shrink the image and place it where I wanted it.

Still in Brush/Paint, I selected a color from the image and painted her hair. I chose another color from the image and painted her hands. Then I changed the settings to select a small brush size, and I set the size variation to its maximum setting. With the same color as her hair, I painted a line down the middle of her dress.

I felt that the pattern of her face was too busy. I used Effect/Blend to blend the same pixels image that I used previously for her face, using my fingers to enlarge it and place it where I wanted it. I used an inverted brush mask to confine the blend to her face.

Using Effect/Blend, I blended a simple geometrical image over my image. I used the Darken blending mode. I used a brush mask over the face and part of the body, to preserve these areas from the effects of the blend. In the brush mask settings, I selected a hectagonal brush from the Basic brush group, and I set a low opacity and small size. Before applying, I used the main opacity slider (as opposed to the opacity slider in the brush mask settings) to slightly reduce the opacity. I used Effect/Raise preset 1 at very low size for added emphasis.