Index: cam.c
===================================================================
--- cam.c	(revision 24100)
+++ cam.c	(revision 24101)
@@ -57,7 +57,7 @@
 	char *argv[128];         /* [0] and [1] are for --cam; the rest point into args */
 	int argc;
 
-	char *old_base;
+	void *old_vars;
 
 	gds_t tmp;
 } cam_ctx_t;
@@ -65,23 +65,22 @@
 static void cam_init_inst(cam_ctx_t *ctx)
 {
 	memset(ctx, 0, sizeof(cam_ctx_t));
-	ctx->old_base = pcb_cam_base;
 
+	ctx->old_vars = pcb_cam_init_vars();
+
 	if (PCB->Filename != NULL) {
-		char *end = strrchr(PCB->Filename, PCB_DIR_SEPARATOR_C);
+		char *val, *end = strrchr(PCB->Filename, PCB_DIR_SEPARATOR_C);
 		if (end != NULL)
-			pcb_cam_base = pcb_strdup(end+1);
+			val = pcb_strdup(end+1);
 		else
-			pcb_cam_base = pcb_strdup(PCB->Filename);
+			val = pcb_strdup(PCB->Filename);
+		pcb_cam_set_var(pcb_strdup("base"), val);
 	}
-	else
-		pcb_cam_base = NULL;
 }
 
 static void cam_uninit_inst(cam_ctx_t *ctx)
 {
-	free(pcb_cam_base);
-	pcb_cam_base = ctx->old_base;
+	pcb_cam_uninit_vars(ctx->old_vars);
 	free(ctx->prefix);
 	free(ctx->args);
 	gds_uninit(&ctx->tmp);
@@ -252,12 +251,7 @@
 
 static int cam_parse_opt(cam_ctx_t *ctx, const char *opt)
 {
-	if (strncmp(opt, "base=", 5) == 0) {
-		free(pcb_cam_base);
-		pcb_cam_base = pcb_strdup(opt+5);
-		return 0;
-	}
-	else if (strncmp(opt, "outfile=", 8) == 0) {
+	if (strncmp(opt, "outfile=", 8) == 0) {
 		char *fn, *tmp = pcb_strdup(opt+8);
 		int dirlen = prefix_mkdir(tmp, &fn);
 
@@ -270,11 +264,20 @@
 		}
 		else
 			ctx->prefix = NULL;
-		free(pcb_cam_base);
-		pcb_cam_base = pcb_strdup(fn);
+		pcb_cam_set_var(pcb_strdup("base"), pcb_strdup(fn));
 		free(tmp);
 		return 0;
 	}
+	else {
+		char *sep = strchr(opt, '=');
+		if (sep != NULL) {
+			char *key = pcb_strndup(opt, sep-opt);
+			char *val = pcb_strdup(sep+1);
+			pcb_cam_set_var(key, val);
+			return 0;
+		}
+	}
+
 	return 1;
 }
 
Index: cam.conf
===================================================================
--- cam.conf	(revision 24100)
+++ cam.conf	(revision 24101)
@@ -6,8 +6,8 @@
 					doc_png {
 						desc export top and bottom copper and silk in 600 DPI pngs
 						plugin png --dpi 600
-						write top.png=top-copper,top-silk
-						write bottom.png=bottom-copper,bottom-silk
+						write %base%.top.png=top-copper,top-silk
+						write %base%.bottom.png=bottom-copper,bottom-silk
 					}
 					{gerber:eagle} {
 						desc gerber export compatible with Eagle's gerber file names
Index: cam_gui.c
===================================================================
--- cam_gui.c	(revision 24100)
+++ cam_gui.c	(revision 24101)
@@ -91,6 +91,16 @@
 	pcb_dad_tree_update_hide(attr);
 }
 
+static void cam_gui_export_cb(void *hid_ctx, void *caller_data, pcb_hid_attribute_t *attr_btn)
+{
+	cam_dlg_t *ctx = caller_data;
+	pcb_hid_attribute_t *attr = &ctx->dlg[ctx->wjobs];
+	pcb_hid_row_t *row = pcb_dad_tree_get_selected(attr);
+
+	if (row != NULL)
+		pcb_actionl("cam", "call", row->cell[0], NULL);
+}
+
 static void cam_job_select_cb(pcb_hid_attribute_t *attrib, void *hid_ctx, pcb_hid_row_t *row)
 {
 	pcb_hid_tree_t *tree = (pcb_hid_tree_t *)attrib->enumerations;
@@ -135,6 +145,7 @@
 						PCB_DAD_COMPFLAG(ctx->dlg, PCB_HATF_EXPFILL);
 					PCB_DAD_END(ctx->dlg);
 					PCB_DAD_BUTTON(ctx->dlg, "export!");
+						PCB_DAD_CHANGE_CB(ctx->dlg, cam_gui_export_cb);
 				PCB_DAD_END(ctx->dlg);
 			PCB_DAD_END(ctx->dlg);