Remove width and height from CCFv2 atlas images (#498)

* Remove width and height from CCFv2 atlas images

Updated image tags for CCFv2 atlases to remove width and height attributes.

* make image widths consistent

Updated image tags for CCFv2 atlases to include styling for better responsiveness.

* use sphinx image width rather than css

Author: PolarBean

docs/source/blog/ccfv2-atlases-added.md

@@ -13,17 +13,26 @@ The mouse brain atlases provided by the Allen Institute for Brain Science (AIBS)
 
 We have packaged the following three atlases: 
 ### 1. CCFv2 Mouse Brain Atlas
-<img src="./images/ccfv2_mouse_brain.png" alt="ccfv2 mouse brain atlas annotations" width="830" height="630">
+```{image} ./images/ccfv2_mouse_brain.png
+:alt: ccfv2 mouse brain atlas annotations
+:width: 830px
+```
 
 **Figure 1. Anterior view of the CCFv2 Mouse Brain atlas annotations and reference image.**
 
 ### 2. CCFv2 Mouse Fiber Tracts Atlas
-<img src="./images/ccfv2_fiber_mouse.png" alt="ccfv2 mouse fiber tracts atlas annotations" width="830" height="630">
+```{image} ./images/ccfv2_fiber_mouse.png
+:alt: ccfv2 mouse fiber tracts atlas annotations
+:width: 830px
+```
 
 **Figure 2. Anterior view of the CCFv2 Mouse Fiber Tracts atlas annotations and reference image.**
 
 ### 3. CCFv2 Developmental Mouse Brain Atlas
-<img src="./images/ccfv2_dev_mouse.png" alt="ccfv2 developmental mouse brain atlas annotations" width="830" height="630">
+```{image} ./images/ccfv2_dev_mouse.png
+:alt: ccfv2 developmental mouse brain atlas annotations
+:width: 830px
+```
 
 **Figure 3. Anterior view of the CCFv2 Developmental Mouse Brain atlas annotations and reference image.**