TO ALIGN IMAGES OR ELEMENTS INTO A SINGLE ROW:
1. Set each image or element to a fixed height.
2. Open the Object & Layout > Align window. Align the objects to a common baseline.
3. Use the Distribute Spacing tool (in the Align window) to equalize the spaces between images: choose a number for the Use Spacing setting.
4. Set the width of the group to a desired size, or stretch the group to fit a desired width.