Sample code to change image resolution in url

ImageResolutionChange.java

protected String replaceImageResolution(String images) {
        int sqIndex = images.indexOf("sq");
        String f;
        if (sqIndex != -1){
            String prefix = images.substring(0,sqIndex + 3);
            String suffix = images.substring(sqIndex + 3);
            char c;
            int startTrim = 0;
            for(int i=0; i< suffix.length();i++){
                c = suffix.charAt(i);
                if (c >= '0' && c <= '9'){
                    startTrim++;
                }else{
                    break;
                }
            }
            f = prefix + "300" + suffix.substring(startTrim);
        }else if (images.indexOf("00x")!=-1){
            String prefix = images.substring(0,images.indexOf("00x") -1);
            String suffix = images.substring(images.indexOf("00x") + 3);
            int startTrim = 0;
            for(int i=0; i< suffix.length();i++){
                char c = suffix.charAt(i);
                if (c != '-'){
                    startTrim++;
                }else{
                    break;
                }
            }
            f = prefix + "300x300" + suffix.substring(startTrim);
        }else{
            f = images;
        }
        return f;
    }