/in/mip.cpp:16:14: error: 'auto' storage class specifier is not permitted in C++11, and will not be supported in future releases [-Werror,-Wauto-storage-class]
        for (auto int j = 0u; j < img.w; j++) {
             ^~~~~
/in/mip.cpp:16:35: error: use of undeclared identifier 'img'; did you mean 'imI'?
        for (auto int j = 0u; j < img.w; j++) {
                                  ^~~
                                  imI
/in/mip.cpp:10:41: note: 'imI' declared here
void readImage(std::istream &is, Image &imI){//read a PPM file into an image array
                                        ^
/in/mip.cpp:24:13: error: use of undeclared identifier 'img'; did you mean 'imI'?
            img.image[j][i].red = (unsigned char)(colorComponents[0]);
            ^~~
            imI
/in/mip.cpp:10:41: note: 'imI' declared here
void readImage(std::istream &is, Image &imI){//read a PPM file into an image array
                                        ^
/in/mip.cpp:25:13: error: use of undeclared identifier 'img'; did you mean 'imI'?
            img.image[j][i].green = (unsigned char)(colorComponents[1]);
            ^~~
            imI
/in/mip.cpp:10:41: note: 'imI' declared here
void readImage(std::istream &is, Image &imI){//read a PPM file into an image array
                                        ^
/in/mip.cpp:26:13: error: use of undeclared identifier 'img'; did you mean 'imI'?
            img.image[j][i].blue = (unsigned char)(colorComponents[2]);
            ^~~
            imI
/in/mip.cpp:10:41: note: 'imI' declared here
void readImage(std::istream &is, Image &imI){//read a PPM file into an image array
                                        ^
/in/mip.cpp:36:19: error: use of undeclared identifier 'img'; did you mean 'imI'?
            os << img.image[j][i].red << img.image[j][i].green << img.image[j][i].blue; //not right?
                  ^~~
                  imI
/in/mip.cpp:31:48: note: 'imI' declared here
void writeImage(std::ostream &os, const Image &imI){//output an image array
                                               ^
/in/mip.cpp:36:42: error: use of undeclared identifier 'img'; did you mean 'imI'?
            os << img.image[j][i].red << img.image[j][i].green << img.image[j][i].blue; //not right?
                                         ^~~
                                         imI
/in/mip.cpp:31:48: note: 'imI' declared here
void writeImage(std::ostream &os, const Image &imI){//output an image array
                                               ^
/in/mip.cpp:36:67: error: use of undeclared identifier 'img'; did you mean 'imI'?
            os << img.image[j][i].red << img.image[j][i].green << img.image[j][i].blue; //not right?
                                                                  ^~~
                                                                  imI
/in/mip.cpp:31:48: note: 'imI' declared here
void writeImage(std::ostream &os, const Image &imI){//output an image array
                                               ^
/in/mip.cpp:122:5: error: use of undeclared identifier 'applyTransformation'
    applyTransformation(imI,imJ,transform,transform_exist);
    ^
9 errors generated.