Suin Edit wrote:

I use powerpoint generate a presentation and add some arrows (outlined) and text on it. But when I use powerpoint save as png, or jpg and view it on Microsoft Office Picture manage and zoom in/out, all characters
and arrows displayed smoothly.

But when I use gimp to view the image, the texts and arrows are not smoothly anymore (zig-zag) .

I don't know much about Powerpoint but my suspicion is that it is a vector based package whereas GIMP is bitmap based. Images and text will look fine in Powerpoint regardless of zoom factor. Once you export data from Powerpoint to a png, or jpg, you now have a bitmap representation of the original. How good that looks will depend on the size and resolution of the image you created at the time you exported from Powerpoint.

I attached my file but I found the mail cannnot be sent.

When sending messages to a mailing list it is always best to provide a URL where the file can be downloaded rather than attaching it to the message. Attaching files to a message being sent to a list is likely to get the message flagged as possibly containing a virus.