Usage:
--------------
put original image "some_image.jpeg" to "/img" folder


get constraned in x-axis by 100px image
/img/100_0/some_image.jpeg

constraned in both axises and crop area defined to s(start)
/img/150_100_s/some_image.jpeg


Params:
----------------
150_100_s
^   ^   ^
|   |   |crop-area
|   |
|   |y-axis constraint
|
|x-axis constraint

[x-axis constraint] - integer value, defined in pixels, which sets
max x size of image
is you don`t need to restrict x sise of img, set this param to "0"(zero)

[y-axis constraint] - integer value, defined in pixels, which sets
maximum image size in y dimension.
if you don`t need to restrict y size of img, set this param to "0"(zero)

[crop-area] - when we cropping original image, there is three variants
of areas, from where disired img will be taken:
    [start=s]   - left part of orig. image if it has landscape orientation
    and top part if portrait
    [end=e]     - it`s right part if image in case of landscape orientation
    and bottom otherwise
    [middle=m]  - is middle in both situations
this param is optional, and by default takes "m" value

Please, note, that both "x" and "y" constraints must be specified.
But one of them can have "0"(zero) value

If you don`t use both "x" and "y", crop-area argument don`t needed too,
because image is always fully fits.