Resizing multiple images at once can be boring work. Adobe Photoshop helps us batch resize images.
Firstly, you have to make sure all the images you need to resize are in same folder.

Step 1 #
Open up one of the images in your resize folder.
Step 2 #
Go to Window > Action
panel. You'll see folder icon named Create new set
at the bottom of the actions panel. Click it and choose a name for your new action. You can then choose whether you want. I named it "Resize It!".

Step 3 #
After creating folder, you have to create a new action by clicking on the folded paper icon next to folder. Now your new action recording.
Step 4 #
Go to Image > Resize
panel. Resize your image.
Step 5 #
Save your image over it. File > Save As
.
Step 6 #
Stop recording. You're done!

Final Step #
Now It's time to use your action. Go to File > Automate > Batch
. Under the Batch settings select the set and action that you created. Then, choose the folder that you want to resize.