Ubuntu – Permission Denied To Delete File

First of all, I'm not looking for an answer on how to remove the files. I am looking for a reason why this doesn't work – and a suggestion on how to remove the files without sudo.

I have a directory in my Desktop that has a few inner directories (don't judge the naming – I just extract what I need from files I'm given) and after getting the files I try and remove the files with rm -rf Bengal\ Tiger\ Creative/, I am surprised to see the following warning for each image.

rm: cannot remove ‘Bengal Tiger Creative/Bengal Tiger Creative/images/customer-services-landscape.jpg’: Permission denied

Below is some code outputs.

tree

nathan@nathan-pc:~/Desktop$ tree
.
├── Bengal Tiger Creative
│   └── Bengal Tiger Creative
│       └── images
│           ├── awards.jpg
│           ├── blank.gif
│           ├── bullet1-light-green.gif
│           ├── bullet2-light-green.gif
│           ├── bullet3-light-green.gif
│           ├── bullet4-light-green.gif
│           ├── customer-services-landscape.jpg
│           ├── desktop.ini
│           ├── header-img1.jpg
│           ├── header-img2.jpg
│           ├── header-img4.jpg
│           ├── header-img5.jpg
│           ├── softhr.gif
│           ├── Thumbs.db
│           ├── tiger_main-img1.jpg
│           ├── tiger_main-img2.jpg
│           ├── tiger_main-img3.jpg
│           ├── tiger_main-img4.jpg
│           ├── Vanquis-benefits-icons_iphone-green.gif
│           └── white-arrow-green.gif

ls -laR

nathan@nathan-pc:~/Desktop$ ls -laR Bengal*
Bengal Tiger Creative:
total 12
drwxrwxr-x 3 nathan nathan 4096 Aug 10 11:30 .
drwxr-xr-x 6 nathan nathan 4096 Aug 10 11:34 ..
drwxrwxr-x 3 nathan nathan 4096 Aug 10 11:34 Bengal Tiger Creative

Bengal Tiger Creative/Bengal Tiger Creative:
total 12
drwxrwxr-x 3 nathan nathan 4096 Aug 10 11:34 .
drwxrwxr-x 3 nathan nathan 4096 Aug 10 11:30 ..
dr-xr-xr-x 2 nathan nathan 4096 Aug 10 11:36 images

Bengal Tiger Creative/Bengal Tiger Creative/images:
total 356
dr-xr-xr-x 2 nathan nathan   4096 Aug 10 11:36 .
drwxrwxr-x 3 nathan nathan   4096 Aug 10 11:34 ..
-rwxrwxrwx 1 nathan nathan  14910 Mar 18 12:29 awards.jpg
-rw-rw-r-- 1 nathan nathan   1093 Mar 21  2014 blank.gif
-rw-rw-r-- 1 nathan nathan   1978 May  8  2014 bullet1-light-green.gif
-rw-rw-r-- 1 nathan nathan   1969 May  8  2014 bullet2-light-green.gif
-rw-rw-r-- 1 nathan nathan   2416 May  8  2014 bullet3-light-green.gif
-rw-rw-r-- 1 nathan nathan   2449 May  8  2014 bullet4-light-green.gif
-rw-rw-r-- 1 nathan nathan 113138 Apr 14  2014 customer-services-landscape.jpg
-r--r--r-- 1 nathan nathan    142 Mar 25 11:58 desktop.ini
-rw-rw-r-- 1 nathan nathan  14312 Mar 23 11:39 header-img1.jpg
-rw-rw-r-- 1 nathan nathan   1480 Mar 23 11:41 header-img2.jpg
-rw-rw-r-- 1 nathan nathan   1278 Mar 23 11:41 header-img4.jpg
-rw-rw-r-- 1 nathan nathan   1168 Mar 23 11:41 header-img5.jpg
-rw-rw-r-- 1 nathan nathan   1703 Mar 21  2014 softhr.gif
-rw-rw-r-- 1 nathan nathan  88064 Aug  4 10:39 Thumbs.db
-rw-rw-r-- 1 nathan nathan  23607 Mar 23 11:56 tiger_main-img1.jpg
-rw-rw-r-- 1 nathan nathan  23400 Mar 23 11:56 tiger_main-img2.jpg
-rw-rw-r-- 1 nathan nathan   6970 Mar 23 11:56 tiger_main-img3.jpg
-rw-rw-r-- 1 nathan nathan   8996 Mar 23 11:57 tiger_main-img4.jpg
-rw-rw-r-- 1 nathan nathan    275 Jul 31  2014 Vanquis-benefits-icons_iphone-green.gif
-rw-rw-r-- 1 nathan nathan   1821 Jul  9  2014 white-arrow-green.gif

Doing chmod 777 and then delete does not work.
Doing rm -rf * inside the directory does not work.
Doing sudo rm file does work.

I can easily remove these files using sudo, however, I cannot see why they cannot be removed without sudo. As a relatively new Ubuntu user, I would like to learn why.

Thanks in advance,
Nathan