I am trying to compress a png and save it as jpg:

```
i = Image.read("http://ds4jk3cl4iz0o.cloudfront.net/e2558b0d34221d3270189320173dabc2.png").first

```

it's size is 799 kb:

```
http://ds4jk3cl4iz0o.cloudfront.net/e2558b0d34221d3270189320173dabc2.png=>e2558b0d34221d3270189320173dabc2.png PNG 640x639 640x639+0+0 DirectClass 8-bit 799kb 

```

I set the format to jpeg and quality to 10 (i.e very poor quality so file size should be greatly reduced):

```
i.format = 'JPEG'

i.write("itest10.png") { self.quality = 10 }

```

The size actually increases to 800kb!

```
 => http://ds4jk3cl4iz0o.cloudfront.net/e2558b0d34221d3270189320173dabc2.png=>itest40.png PNG 640x639 640x639+0+0 DirectClass 8-bit 800kb 

```

1) Why? 

2) How can I compress the photo so the size is < 150kb ?

Thanks!