To identify the degenerative discs you need pictures of the transverse and coronal planes as well. In any case, L4-L5 (earlier stage) and L5-S1(more expressed, perhaps protrusion or prolapse ?) are degenerative discs. 

It is not clear if all images are from the same patient (there is a prominence of the anterior thorax on the first, lesser on the second and clear again on the fourth image). As correctly mentioned it will be necessary to have all views of all planes as well as T1 and T2 images. In these images there is evidence of a bulging disc on L5-S1 and this possibly if the most striking area of abnormality. Second image shows that L4-5 has also a problem not visible in other films clearly; possibly the last. There is indication of narrow levels above (if the pictures belong to the same individual (levels of T11-L2)) and this may indicate an element of misalignment but this cannot be said for certain without all plane images.

I agree with George.

In my opinion of course I want to see all axial images in these patients.

In these six sagittal lumbar MRI images, L5-S1 level is pathologic segment, may be it occurs lumbar disc degeneration, lumbar disc protrusion, or black disc present also. 

Finally, I also agree with George Zafiropoulos opinions too.

Tarık Akman, MD.

@Tarik AKman,@Fadi @george @ panayot  i'm working on spine images.i dont have a collection of images. can you share a set of images which are healthy as well as degenerative

i'm using the following

http://spineweb.digitalimaginggroup.ca/spineweb/index.php?n=Main.Datasets

Dataset 7: Intervertebral Disc Localization and Segmentation: 3D T2-weighted Turbo Spin Echo MR image Database

The database consists of 3D T2-weighted turbo spin echo MR images of 15 anonymized patients, each containing at least 7 intervertebral discs (IVDs) of the lower spine (T11-L5, Fig. 1). Each patient was scanned with 1.5 Tesla MRI scanner of Siemens (Siemens Magnetom Sonata, Siemens Healthcare, Erlangen, Germany). For each IVD, reference manual segmentation is provided in the form of a binary mask. All images and binary masks (one binary volume per patient) are stored in the Neuroimaging Informatics Technology Initiative (NIFTI) file format.

To me only the image 06 shows fairly healthy discs the other 5 images show degeneration of discs.