You don't need Photoshop or some other advanced piece of software to resize a large number of images at once. You can use Microsoft Office Picture Manager which is part of the Office suite.
When you want to copy the result of the cell to another cell in Excel, the target displays an invalid references error messag. This error can be avoided by copying cell value into target cell and not the whole formulas.
In Microsoft Excel you can use formating tools like colors, text alignment, font styles and many more to make your sheets look nicer and more transparent.
