How to change default image size?

How to insert new size:

1. Login to admin panel,
2. Click on the “Preferences“ and on the “Image” tab,
3. Click “Add new” button,
4. Insert resized image name and parameters, select categories,
5. Click “save” button.

How to edit:

1. Click on “Edit” button,
2. Set new parameters,
3. Save new parameters,
4. Go to bottom page,
5. Create new image size – click on button “Regenerate thumbnails“.