Viewing, Compressing, and Processing Images with Graphic Converter

Tom O'Haver
Professor of Analytical Chemistry
Department of Chemistry and Biochemistry
and Maryland Collaborative for Teacher Preparation
The University of Maryland at College Park
June 12, 1995
Graphic Converter is an excellent shareware program for performing a number of useful manipulations on images. You can download it from Please pay the shareware fee ($35) if you intend to keep and use this program.

* To open a picture with Graphic Converter, you can either:

(a) drag the icon of the picture and drop it off on top of the icon of Graphic Converter,


(b) launch (double-click on the icon of) Graphic Converter, then select Open from the File menu, navigate to the desired file, and double-click on the file name.

* To save a graphic file in compressed PICT format (for use in Hypercard, word processors, KidPix, etc):

  1. Select Picture --> Compression settings --> Still Image.

  2. From the Compressor pop-up menus, select Photo-JPEG and Best Depth, then set the Quality to Medium or High, then click on OK.

  3. Select File --> Save As... , select PICT from the Format pop-up menu and Quicktime from the Compression menu, navigate to another directory if desired, then click Save.
* To crop (cut off the edges) of a picture:
  1. Drag the + cursor across the picture to frame the desired area in a dotted rectangle. (If the cursor is not a +, select Picture --> Show Toolbox..., then click on the dotted rectangle tool in the toolbox).

  2. If necessary adjust the position of the rectangle by dragging the small black "handles".

  3. Select Edit --> Trim Selection.

  4. Note: to crop to a specific size, select Picture --> Show Position before cropping. The size of the dotted rectangle will be displayed in the title bar of the window as you drag.

* To shrink or expand a picture (make it larger or smaller):

  1. Select Picture --> Size --> Scale...

  2. To change the size of the picture by a certain factor, click on the Factor button and type in the desired scale factor into both the x and y boxes. For example, if you type .5 into both boxes, the picture will be reduced to half-size. If you use different factors for x and y, the shape of the picture will be changed. Note: small pictures will not look sharp when enlarged by large factors.

  3. To force the image to a specified size (in pixels), click on the Size button and type in the desired size, in pixels. (For use with the "LargePicTemplates" the desired size in 320 X 240; for use with the "SmallPicTemplates" the desired size in 160 X 120).
  4. Click on OK.

* To make a border around a small picture so that it fits in a specified larger size:

  1. Select File --> New. (Or type [[apple]] -N)

  2. Type in the desired overall size, in pixels. (For use with the "LargePicTemplates" the desired size in 320 X 240; for use with the "SmallPicTemplates" the desired size in 160 X 120).

  3. Open the small picture and click on its window.

  4. Select Edit --> Select All. (Or type [[apple]] -A)

  5. Select Edit --> Copy. (Or type [[apple]] -C)

  6. Click on the window of the

  7. Edit --> Paste. (Or type [[apple]] -V).

  8. Drag the center of the image to center it as desired. (If desired, you can fill the border with any desired color by using the "paint bucket" tool in the Toolbox (Picture --> Show Toolbox)).

* To change the contrast, brightness, color balance or color saturation:

  1. Select Picture --> Brightness/Contrast.

  2. Adust the sliders until the picture is as desired.

  3. Click on OK.

* To sharpen the image:

  1. Select Effect --> Edge Enhancement...

  2. Set the Value to 15%.

  3. Click on OK.

* To manually "touch up" a picture (erase flaws, etc.)

  1. Select Picture --> Show Toolbox...

  2. Click on the desired tool and apply to picture. See the documentation included with the program for more details.

* To
"dither" a picture so that it looks better when displayed in 256 color monitor settings (prevents "posterization" effect).

  1. Select Picture --> Colors --> 256 Colors (8 bit)

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This page is maintained by Prof. Tom O'Haver , Department of Chemistry and Biochemistry, The University of Maryland at College Park. Comments, suggestions and questions should be directed to Prof. O'Haver at